The World’s Most Efficient Air-Conditioner

Well, I’m finally done building that fence I’ve been meaning to build for the last few years. It came out great, and now we at last have the nice, private yard that this house of ours deserves. But as with every do-it-yourself project, other unexpected benefits were revealed as well, and one of them was that I ended up with a free air conditioner of unsurpassed efficiency.

To get this fence built Mustache-style, I didn’t whip out my cell phone and credit card and call a fence contractor. I had to do it myself, and since it was my first large-scale fence (about 180 linear feet at 6 feet of height), I kept track of some of the stats.

I had to set 25 posts of treated lumber into the ground. The posts were each 8 feet long, weighing 30 pounds each and set into about 80 pounds of concrete. Of course, before setting each post I had to carefully line up and carve a 2-foot-deep hole in the rocky, dry Colorado hardpan soil. Each of those 80-pound piles of excavated soil and rocks was the result of several minutes of wrestling with a burly electric drill equipped with a 3″ soil auger (a very useful invention!) followed about 100 blows with a manual post-hole digger, and occasional attacks with a sawzall to cut through roots, a diamond blade grinder to cut through concrete, and a handheld jackhammer to chip away anything that remained. And all those holes were just to get me to the point of hand-mixing over 2000 pounds of concrete, manually tailoring, drilling and screwing over 100 cross pieces, and nailgunning in 500 cedar planks, cutting and bending each to coax their naturally-curvy demeanor into the extremely tight and straight fence that I wanted.

All in all, it was about 69 hours of work, and it was done through a period of record temperatures in my area. Some days topped out at over 100 degrees Fahrenheit (37C), and few were below 80. Half of the fence is in full sun, leaving me with only SPF 80 sunscreen and my sun hat for shelter.

But a strange thing happened as the days went on and the fence sections were completed, one after another. I stopped noticing the heat, and started feeling downright comfortable. The improvement was so dramatic that I thought it was the weather that was changing rather than me. Often I’d walk past my outdoor thermometer on the way to refill my water mug, and be shocked to see another mid-nineties reading, when I felt like it was under 80. And at the end of each day, I’d find myself inside the house feeling comfortable even with a shirt on, noticing an indoor thermometer reading above 85. In previous years, I had felt the need to turn on the air conditioner at around the 80 mark. Morning house temperatures in the high 60s suddenly felt bone-chilling to me, even though in the winter I normally curse the stuffy house and go outside to get some fresh air if someone turns the thermostat above 67.

What I had done with all this work in the heat is given myself the gift of Heat Acclimation. This is a form of Badassity that is not just something made up by the most spartan of Mustachians. It’s a real and scientifically measurable body adaptation – a gift of comfort that YOU should give yourself this summer, because the benefits are enormous.

To get some of this goodness for yourself, it helps to understand what it is.

When a normal office worker encounters unusual heat, his body tries to cool itself by sweating. The body also circulates heated blood out near the skin’s surface, allowing heat to radiate and convect through the skin and evaporating water. That’s why overheated people often appear more reddish in color.

The problem is that this leaves less blood in the core of the body where the muscles are working, and it requires a higher heart rate for any given volume of work. In short, you slow down at whatever you are doing, and if you push too hard you start feeling like shit and just want to lie down in the shade.

But when you’re out in the heat, your body is starting to wise up to the situation. It creates more blood, the endurance of your sweat glands increases, and the ability to sweat efficiently at the first sign of heat increases. You really do become a Badass Heat Survival machine, and research indicates that you’ll see significant results within just one week of spending an hour or so outside in the heat doing light exercise like walking or biking. I’d estimate that my own acclimation has sliced about 12 percieved degrees Fahrenheit off of this summer’s heat.

The more you do it, the better you get, as witnessed by the Phoenix-area MMM readers who insist that they can easily bike to work year-round in that hot desert city where daytime highs are rarely below 40C (104F) for months on end. This also explains the amazing abilities of my Mexican concrete subcontractors back in the house-building days. These guys would often work alongside me on searing-hot days in black jeans and long-sleeved Denver Broncos sweatshirts, while I could barely survive with a white t-shirt, dark sunglasses, and enormous straw sombrero.

In other words, when someone says, “You can’t spend time outside where I live, it’s TOO HOT!”, it’s really equivalent to saying, “You can’t bike to the grocery store where I live, IT’S FOUR MILES AWAY!” – it’s not a question of impossibility, just of acclimation.

But this post isn’t really about extreme heat survival, like those 120F Phoenix days. It’s about a much easier and more relaxing kind of heat acclimation – making the most out of your own climate in the summer months.

During the peak of the last hot season, I wrote a rant called “How Not To Use Your Air Conditioner“, where I railed on the excessive use of A/C by modern people. This year, I’m doing it again, but with the added perspective of this new experience of extreme heat acclimation, because it works better than I thought.

Here’s an interesting fact: because my house is fairly well insulated and captures a lot of winter sunlight, it acts as a significant buffer against weather changes. I’ve measured that even without a furnace and with no air conditioner, the temperature in here would never go below 40-50F in the winter, or above 86F in summer. In other words, if I were badass enough to put up with the full range of those temperatures, I could run with zero heating and cooling costs indefinitely. 100% of my costs (about $450 per year) are to fine-tune that temperature to allow my family a more luxurious lifestyle.

So as your wimpiness increases, so do your heating and cooling costs. At the extreme end of the spectrum, some people are such heat wimps that they cool their house to the meat-locker temperature of 72F in the heat of summer. You can spend $200 per month keeping a house that cold, even while the house’s natural temperature without cooling might be barely above 80.

Gaining heat acclimation in the summer (and cold acclimation in winter) is about more than just utility bills. It also opens the world back up to you, allowing you to get out and do things that you’d normally wimp out of doing.

A common lament across America these days is this one:

“I know Mr. Money Mustache taught me I have to get my groceries with a bike trailer, and I’ve been doing it all spring. But now it’s just so hot out there, and he doesn’t know where I live so he won’t see me… so I think I’m just going to sneak out and use my air conditioned car until the hot season ends”.

When Junior Mustaches pull stunts like that, they think they are fooling Mr. Money Mustache, but they are really just fooling themselves. Riding around in your climate-controlled car is just like taking another shot of heroin to prolong a lifetime habit. Instead, you can kick the addiction to comfort, go through the necessary downtime, and be free for life (see: Trainspotting).

So let’s just try this experiment: get yourself out in the heat for at least a few minutes every day. Not just walking to the car, but seriously out in the heat. Go for a walk, try a run if you’re a runner, bike to work, even go out fishing. Drink loads of water (during my fence work I went through about 4 32-ounce jugs of icy water every day). And eat a banana or two to help replace electrolytes lost through sweating.

Instead of increasing your suffering, you’ll actually be building your ability to stop suffering. Take it up to an hour a day. Increase your A/C temperature by one degree every day or two. Watch your need for air conditioning drop drastically. Watch your enjoyment of the outdoors increase. Watch your Money Mustache grow.

A cautionary statement, not that people like MMM readers need these things: heat CAN be dangerous. Your body does need to keep its core temperature within a certain range, otherwise bad things happen. As physical fitness decreases and age increases, so does the risk of overheating. That’s why when record heat waves strike, you always read about a bunch of elderly people kicking the bucket in their non-air-conditioned apartments.

On the other hand, if you carefully and gradually push your comfort boundaries, just as with any form of other exercise or badassity training, you tend to extend those boundaries in a positive way. I try to spend at least an hour a day doing something at least mildly uncomfortable. Just as I once suggested that we should all learn to appreciate mild hunger, it is also nice to appreciate mild discomfort. Without it, you are on the slippery slope to lifetime wimpiness, a place much worse than mild discomfort!

I can see it’s back up in the nineties outside there today. Full sun and no wind. It’s far too comfortable down here in my basement office, so I’m going out for a ride!

  • Knince June 14, 2012, 11:51 am

    Awesome post MMM! My wife and I haven’t used A/C in our home or our vehicles for 2 years, and it’s the best move we’ve made for growing our Money Mustache! We get to save $$ on utilities and BONUS: we can also poke fun at all of the wimpy A/C users. Aw yeah.

    Thanks for the article!

    • brkr12002 June 18, 2012, 7:32 am

      Same here. My utilities and water are about $40 month.
      I have a renter living in the same size place and his utilities are typically $150 monthly. He usually can’t believe how much he spends on it each month, but walking into his place it’s freezing cold and he has a window cracked. Some people are clueless.

    • cynthia June 19, 2012, 3:34 am

      GREAT Article! and here’s another tip we learned in Thailand from locals, right after we arrived and had spent a few days ‘dying’ from the heat: you feel like crap because of eating too much fat which makes your blood thicker, sluggish. So cut down to fruits juices light stuff, and throw in some spicy chilis/ hot curry, which thins out your blood and makes you feel better. Worked like a charm for me and I enjoyed the rest of my time there without A/C!

      • Raech July 12, 2012, 3:13 pm

        Yea! Thanks for the tip! Love it, and it makes so much sense!

      • Joe Schmoe, MD July 3, 2018, 9:27 pm

        I’m glad you enjoyed your time in Thailand. However, I am a bit skeptical about the dietary recommendations here. It would be surprising if dietary lipid intake (“fats”) had a significant influence on your serum lipid levels in excess of the influence on total caloric intake. The latest research shows fat intake does not have uniquely deleterious health effects.

        In reality the body is very effective at regulating the concentration of different blood components and they would be expected to fall within the normal range unless you are fairly sick.

    • Eric July 12, 2014, 3:24 pm

      Above about 40 mph (depending on the vehicle), it is actually more fuel efficient to use your car’s A/C than to open the windows all the way, because of the added drag.

      Though if you’re doing it because you don’t have A/C in the car or don’t want to shell out the $$ to repair it, then more power to you!

  • Sara June 14, 2012, 11:56 am

    True badassity at work here! And absolutely true. When I worked from home I would go weeks with little exposure to air conditioning. And I adapted fairly easily to heat and humidity. Working in air conditioning now really does affect my adaptation. And let’s not forget the cultural “requirement” of never, ever sweating…

    • Knince June 14, 2012, 12:07 pm

      I feel your pain Sara! I have to wear a fleece jacket in the office during the summer thanks to the 72 degree thermostat… brrr. To coworkers that think I’m crazy, I point out that humans have survived without those dang air conditioners for many many years.

      Also, I spent some time in Manila, Philippines and so I can reinforce your comment that “no-sweat” is definitely cultural. Most people there don’t have home air conditioning, and they live on the freakin’ equator! Yet, they hardly sweat and just carry an extra shirt to change into if needed.

      Definitely hardcore.

    • Mr. Money Mustache June 14, 2012, 12:07 pm

      Yeah – the worst is the excessive air conditioning used in public places. I was at a pub the other night (with an Australian MMM reader actually), and we noticed it was ice cold in there (probably 72F or so) after it had been a 100F day outside.

      This is just making the eventual heat feel worse for the customers. Instead, why not set the A/C to just cool enough to be comfortable, and scale that as the summer heat rises. So in Phoenix, buildings would be cooled to 86 since everyone is coming in from temperatures of 110 – it would still feel very refreshing. Here in Colorado, you might cool to 82 or even 80. But 72? That’s just impractical.

      Meanwhile, I’ve noticed a tradition in Hawaii of fairly minimal A/C use compared to the mainland, despite a fairly hot and humid climate. The culture is just slightly different such that people are willing to let their bodies do the air conditioning.

      • Uncephalized June 14, 2012, 12:21 pm

        I HATE walking into a store or office building from 110 degrees outside temperature and having it feel like winter inside. It makes me physically tired–I think the repeated stress of adapting to wide temperature swings is very hard on the body.

        Hawaii is usually better with the little retail stores, but in Honolulu at least they still tend to go Antarctic in the larger malls.

        • Debbie M June 14, 2012, 2:42 pm

          Working at an overnight summer camp near Houston, I learned a few things about how the heat affects me.
          1) It generally took me about 3 days to get used to it after living indoors. Getting used to it included learning to sleep on my back. I would have expected side-sleeping to be cooler (more exposed surface area), but no.
          2) Being in my mom’s house during breaks from summer camp generally took about 6 hours to get used to.
          3) None of us got sun tans because we stayed in the shade whenever possible (in other words, whenever we weren’t swimming or canoeing).
          4) Being in the sun (canoeing) with no hat = getting a headache. Admittedly, I only tried that once. I don’t know if the brain can get used to being deep-fried.
          5) Moving to grad school in Austin directly from summer camp one year was difficult. Austin is much less humid, but my campus had much less shade and much more concrete than my camp, and all the buildings were refrigerated. (Sadly, I now work in these refrigerated buildings.)

          I find it hard to believe that being outside only an hour a day can make such a big difference. Maybe it was because you were also using less AC as you went along.

      • Matt June 14, 2012, 2:35 pm

        I wouldn’t say Hawaii is hot or humid. I mean with temps ranging from 72-85 and humidity around 55% I wouldn’t consider it a great feat for not using A/C there.

        • Greg June 15, 2012, 3:35 pm

          Back in 1968 when I was a pre-teen we lived in Navy housing for a year. The houses had no heaters, no air conditioners and no insulation. The exterior walls were 3/4 inch thick boards. We had a huge screened-in lanai and it was comfortable year round.

      • JJ June 14, 2012, 3:47 pm

        Ha, the alfresco dining scene on Pearl St Mall last night was right on the money, but that would have needed a car…

        Great article and I’ve observed the same when we lived in Perth, Oz (dry, v.hot long summer). From my personal observation it doesn’t seem to work quite so well in a crazy humid environment as it is a lot harder to shed the heat, but obviously many people do function ok.

        As an aside, one of my pet hates when I’m on the road for work is being sealed up in a hotel room with windows that are glued shut. It would be nice if TripAdvisor showed who lets you breathe at night.

      • gzt June 15, 2012, 10:08 am

        Hawaii is warm, not hot. The temperature is very, very constant in most places. For instance, if you look at Honolulu, the average high for today’s date is 87 and the average low is 72. That’s warm! But the record high is 90 and the record low is 67. Not much different, and not hot. It just doesn’t get hot, the ocean very strongly moderates the temperature. Sure, depending on where you are on the islands, you might get more or less variation. And most mainlanders wouldn’t think twice about turning on the AC if it’s 85 degrees every single day. So, yeah, there’s definitely a cultural difference and we could learn from them. But getting by without AC when it’s 85 every single day is a little different from getting by without AC when it’s 95 some days.

        • Mr. Money Mustache June 15, 2012, 2:52 pm

          > But getting by without AC when it’s 85 every single day is a little different from getting by without AC when it’s 95 some days.

          Exactly! Tell that to the Great Lakes and North Atlantic Coast regions, please, where people run their A/C on 79F days, just so the house can stay 72.

          • Oh Yonghao September 19, 2014, 1:54 pm

            We took advantage of our neighbors A/C usage and the layout of our properties. Essentially our patio/backyard is all the space between our house and theirs. The drip line for their central unit goes out into our patio. We just put a bucket there and used the water to keep our plants healthy during the spring. The strange thing is we noticed this happening when it was still 75F outside.

            We still do not know if our A/C works, it’s a central air unit and we haven’t turned it on all year. We moved in the winter so our house inspector couldn’t test it either.

            I have a friend who tries to keep his office 72F and has electric bills all year of $200-$300 (electric heat also). Our house on the other hand has hit 86F once after a night that we got the house down to only 65F. So far it’s been since August and I haven’t even had to open the windows to keep it cool.

      • Matt June 15, 2012, 10:58 am

        MMM, I’ve always assumed for-profit public places (e.g. the pub you were at) consider it a competitive advantage to keep places ultra-cool. Consider that the average non-Mustachian consumer is on a downward spiral of hedonistic adaptation. Why not cater to this and keep the place cooler than the competition? I suspect that a lot of marketing research dollars has determined that most people will find a certain temperature (e.g. maybe it’s 72) most comfortable.

        • seth June 22, 2012, 3:04 pm

          Having worked for a restaurant franchise in the past, you are correct, but not in the way you think.

          One reason business keep the places ‘too’ cool is to keep people from staying too long. Same with the seats, don’t want them too comfortable. Same with background music. Just a little too loud to make people just a little uncomfortable.

      • Raech July 12, 2012, 3:18 pm

        Agree, but we noticed that even in the winter a lot of restaurants are cooler – and it drives me nuts. Finally ran across the reasons why – if it’s colder, you are more likely to eat more/order more = they make more money. (I noticed Applebees to be the biggest offender in my neck of the woods) I usually just bring a coat now, but Jeez, do I get ticked (at myself) when I forget!

        • Oh Yonghao September 19, 2014, 2:05 pm

          In Taiwan it can be hit and miss. At least half the places I eat there are no air conditioning, and that is excluding the ones that are the equivalence to a hot dog vendor. Most actually just run fans. The shaved ice shops do pretty well there.

          When you get into the bigger restaurants, ones where you have wait staff and such, then you get into a fairly consistent air conditioning environment. This will vary between being comfortable at around 80F, or being chilly at 72F.

          Then you have all the clothe stores which seem to blast their A/C with no worry of waste. Some shops even have large glass doors propped open with the A/C on full.

          There is also the food market which is housed in an open fashion, basically a large structure with a roof, but no A/C and plenty of vendors on every side of the street making it nearly impossible, and I say nearly because some do squeeze through, to drive a scooter, let alone a car, through. This market is open every day, and was the place we went for the majority of our food.

  • KittyWrestler June 14, 2012, 12:02 pm

    Human body can for sure endure whatever the condition throwing at them… I grew up in China so “what is air condition?” I remember those 44 degree days (probably well above 110F) and when I woke up from my nap, my bamboo sheet was soaked with sweat.. but you live..

    I think anybody can do the 90’s… (actually if it were 90’s, it felt cool!! with breeze? that’s heaven!), 110 is a different story since you could hardly breathe, but you make it work.. :)

    We never had AC in China so at night, every kid came out to the Ally and we sat in circles to exchange stories or listen to some stories on radios together.. It really did wonder to bond human beings.

    Coming to US, everybody shuts their door.. man.. I kind of miss the poor country life u know!

    • Gerard June 14, 2012, 4:05 pm

      Most of my neighbours in my (non-air-conditioned) Toronto high-rise are from Bangladesh, and they have summer totally figured out. At 11 at night, everybody’s outside, grownups talking, kids riding their bikes and playing cricket… it’s great. And it makes the neighbourhood safer. I totally get what you’re saying.

  • Tara June 14, 2012, 12:05 pm

    It gets toasty warm and freezing cold in Montreal – I never use AC and try to keep the heat down as much as possible in the winter. You really do get used to it when you are not constantly trying to keep the temperature inside a tight range. Sure does help the Hydro bills.

  • Uncephalized June 14, 2012, 12:14 pm

    I have been leaving the A/C off on my commute for the past couple of weeks and it is doing good things for my heat tolerance AND my gas mileage. But I also have a habit of taking a walk around midday, no matter what the outside temperature is (I’m one of those Phoenix residents so it’s quite hot!), so that helps too.

    And yes, MMM, I know I need to stop driving my car to work. :-D I’m working on it–looking for a scooter and a replacement for my old bicycle. It’s a nice bike but it’s an older road bike with very low handlebars and downtube shifters, which kills my neck and shoulders if I ride it more than a mile or two (I have some chronic neck issues from an injury in high school). Once I get something that has a more upright seating position I’ll start working up to bike commuting. Hopefully I’ll find a decent scooter soon too which would be a great compromise. I’m not sure I’m Badass Enough to start biking a 30-mile round trip commute in the middle of the summer–that might have to wait for cooler months so I can work up to it. Just have to convince my wife to let me sell the truck to pay for it! With what our truck is worth we could get an ’04-’05 xA, a utility trailer for it and a 50cc scooter and probably still put a little cash in the bank.

    And yes, I also know we need to move closer to work. Working on the wife on that score too. Moving is very stressful and she doesn’t want to do it, but we’ve got 9 months left on the lease and I’m sure she’ll come around by then.

    • Tanner June 14, 2012, 12:39 pm

      <—-PHX resident too. Also my main bike is an old road bike with downtube shifters. I love it! It could be that the bike is too small for you? But the nice thing about those old road bikes is you can switch to mountain bike riser bars fairly cheaply because you don't have to replace the shifters. If you are in downtown area go to the Rusty Spoke bike co-op or if you are in the east valley you can go to Bike Saviours bike co-op. Or heck I could help you out :) and get you biking in no time! I have some old parts lying around although not the nicest quality could get you in that more upright riding position.

      • Uncephalized June 14, 2012, 1:11 pm

        I hate the downtube shifters. I tried to get used to them and found that I ended up leaving my bike in a middle gear all the time because it was too much hassle to reach way down to shift all the time. It made me feel unstable, and I really don’t like taking my hand off the bar where I can’t brake on a moment’s notice if needed. I want a bike with integrated shifters on the handlebars.

        The bike is not too small–I have the seat height adjusted to where my legs get proper extension and the pedaling mechanics are fine. It’s just that all road bikes seem to have very low, forward handlebars–and my neck and shoulders can’t handle the stress well for long periods. I get bad headaches. So I want something configured more like a commuter bike, with a comfy rise to the bars, and shifters easily at hand. I might just take the opportunity to learn to build my own bike from components–which is something I’ve kind of wanted to do for a while anyway–and then I can pick everything just the way I want it. :-)

        Thanks for the offer of help though! I might just take you up on it if you’re not careful… I am near downtown, in the Coronado neighborhood.

        • Tanner June 14, 2012, 1:58 pm

          One nice thing about biking in Phoenix is it’ so flat you really don’t need to change gears that much. But I can understand the love/hate with downtube shifters. You’re only a few miles away. I’m in North Park Central Neighborhood. Contact me through my blog if you want to get together sometime and tinker on your bike.

    • Hcat April 15, 2017, 6:20 am

      First off, you’re renting and can move. Most people nowadays change jobs more often than they change residences, and don’t wish to be limited to the job opportunities close to their home. Or the shopping opportunities.

  • Heath June 14, 2012, 12:18 pm

    Oh man, before this post, I would definitely have been one of the Junior Mustacians who was fooling myself. I lived in Phoenix for 24 years, and never really got used to the extreme summer heat. It was one of my primary reasons for Getting The Hell Out Of There. Looking back, I guess it could have been my extreme hatred for the heat that led me to keep suffering (because I was always avoiding it). Upon my return, I shall have to embrace discomfort, in order to become comfortable…as much as that still sounds bat-shit crazy to my whinypants heat-weakness. DAMN IT!

    • Uncephalized June 14, 2012, 12:23 pm

      There are many, many other reasons not to live in Phoenix besides just the heat. The complete un-sustainability, its giant sprawling cancerous growth, and sheer ugliness are all good enough reasons for me. We’re getting outta here as soon as we can manage it.

      • Llama June 14, 2012, 12:34 pm

        I left Phoenix after having my car broken into then my house twice, and having the cops tell me “Well, we’re really busy so no, we can’t drive by your house once or twice tonight while your window is still shattered.”

        But yeah, F the heat too!

        • Tanner June 14, 2012, 12:57 pm

          PHX isn’t as bad as you make it out to be. There are some downsides (just as any city) as mentioned but so many positivies if you are willing to look for them. Granted I would love to move to California but the cost of living here is so affordable and i have never had any problems finding a new job. You do not have to be a part of the urban sprawl. Tempe or downtown Phoenix are great cities. Plus Sun 300+ days a year, great culture and ever improving biking infrastructure.

          Thousands of people don’t come here to retire for no reason. This is a great Mustachian City that is starting to more forward thinking.

          • Sarah September 26, 2012, 12:04 pm

            I just can’t understand the 300+ days of sun argument. I moved to Texas in the middle of a drought, and the saddest thing to me was the lack of rain. I love rainy days and was in heaven when it returned this spring. I can’t wait to return to the East Coast and the Rainy weather.

        • Nice Joy April 15, 2017, 12:09 pm

          Phoenix has very low tax.
          Lot of great schools …
          feel good sunshine .
          Any day you can get out side with out extra clothing.
          Best roads. You don’t need navigation here.
          Any day is good for any project.
          Heat is not bad when you are in shade . that too only 3 months.
          Lot of bike lanes.
          Lot of hiking trails.
          Affordable housing. and many more.

  • Llama June 14, 2012, 12:31 pm

    I just got back from visiting my mom in the Cincinnatti metro area. She has a nice house out in the suburbs, with nice big trees and a breeze that goes through.
    Bedtime the first night I wanted to open my window for fresh air, but she said the window had been stuck and not opened for over 2 years. So I investigated, and within 20 minutes we had that sucker opened. She kept offering to just put the air on for me, but I couldn’t see the point, since it was in the 60s outside!
    The next day, she was telling me about how she’d love to enclose her back patio into a room so she could sit out there. Well, she had a perfectly nice set of table and chairs out there, plenty shade for the daytime, and in any case she never opened the shades in her house much less the windows! Hell, if she’d replace her storm door with a screen door for summertime at the front of the house and open the back she could have gotten a really nice cross-breeze and probably drop the internal temps 5 degrees!

    Back at home in SoCal, we almost never run the AC. Maybe 2-3 times all summer. I’m perfectly happy to change into lighter clothes and sip an iced tea in the shade, or jump in the pool if it gets really bad. One year we discovered that it costs over $10 in electricity just to run the AC overnight. Worth it if we have guests, but not for just us!

  • Virginia June 14, 2012, 12:36 pm

    I might be a wimp or complainy-pants on this one. I hate the heat although I seem to be able to handle cold temperatures better than most people. Our electric bills don’t seem that expensive though. They usually run about $50/month in the summer. We have one of those programmable thermostats that basically doesn’t cool the house between 8am-5pm and keeps it at 72 when we are home.

    • da55id June 15, 2012, 6:12 am

      I agree. I had my DNA snps sequenced, and discovered that both my maternal and paternal lines are all from extreme northern points in Europe (Tunguska Siberia!). I have NO problem with the cold, but heat has always been a BIG issue for me. So, I use airconditioning at a reasonable setting (76ish) without embarrassment – so there!

  • Nurse Frugal June 14, 2012, 12:41 pm

    I totally see your point Mr. MMM. I recently started running mid-day due to schedule reasons and was very reluctant at first. In Southern California it can get as high as 90’s at that time of day, and I was used to running first thing in the morning when it was nice and cool. I decided either I be a lazy slug or I just get up and run in the middle of the day. What a difference!!! It’s only been about 2 weeks and my body has already adjusted to the hot temperatures during the hours of noon-2pm! It’s like I retrained my body and built up my heat tolerance! I agree, no more Mrs. Complainy pants here……….it’s a decision to get past the difficulty of adjusting the first couple of days and I think it went smoothly ;)

  • Brave New Life June 14, 2012, 12:46 pm

    My father in law was visiting a few weeks ago and when the house hit 80F, he went and turned on the A/C. Seeing that it was 6PM and the cool Colorado night was about to come upon us, and also because my wife and I like to torture his anti-Mustachian spirit, she snuck back over there and turned it off. I was so proud of her!

    A few minutes later, as I was wrapping up some work and my wife was working on dinner, My father-in-law once again went back over to the thermostat to check the thermostat, checked the temperature, noticed the A/C was off again – and so he turned it back on. At this point I called him out as being a wimp and let it be – he was leaving soon anyways.

    On an aside….

    Later that night, he laughed at my wife and me for buying and selling things on Craigslist. So I laughed at him for still working full time at 65 at a job he doesn’t enjoy. We have great relationship. :)

  • Brave New Life June 14, 2012, 12:47 pm

    MMM – It’s worth pointing out that cold acclimation also exists. Coming from Texas to Colorado, I had the heat part down but not the cold. But a winter of riding my bike to work and I’m now an eskimo compared to the lifelong Coloradians in my office.

    • Jamesqf June 14, 2012, 1:18 pm

      True, and I acclimate to cold better than to heat. We do need to remember that people lived in those too hot/cold areas long before A/C was invented.

      I almost never use A/C in a car, because to me it is just so darned uncomfortable to have the cold air blowing on you, while parts of your body near the windows & roof are still hot. One trick for the really hot days is to carry a spray bottle of water. Spray the dash, steering wheel, and seats before getting in, and give yourself a spray now & then.

      I don’t use home A/C either, but that’s because of good insulation, and an intermountain climate that cools into the 50s even on days when the high tops 100.

      • Matt June 14, 2012, 2:41 pm

        I grew up on the gulf coast of Texas and remember learning about the Indian tribes that inhabited the land in our area and thinking I cannot imagine how/why they would live here without A.C and all of the mosquitos….come to think of it I wonder why I’m still here lol….I’ll start searching for jobs in CO now.

    • Tyler June 14, 2012, 2:03 pm

      Good point. And as a native Texan who lives in the Bay Area, I can also testify that reverse acclimation also exists. Use it or lose it.

      • Karawynn @ Pocketmint June 14, 2012, 11:14 pm

        There are inherent physiological differences between people, though, and I for one have had little success altering mine.

        I also grew up in Texas; I don’t know whether to attribute it to nature or nurture, but I deal with heat very well. I think 85F is perfectly comfortable; I’m usually the last person in the room to break a sweat.

        But even after 22 years in the north (2.5 in Chicago, 2.5 in NYC, 17 in Seattle), I am STILL not acclimated to cold. We don’t heat the house above 68F, but I require supplemental electric heating pads and space heaters to get by.

        At least part of it is identifiably medical — I have a moderate case of Reynaud’s disease, which is a circulation problem in my extremities. Temperatures below about 55F are painful, sometimes excruciatingly so. Digging something out of the deep freezer is like sticking my hand into a gom jabbar box.

        Oh, and my resting body temperature is about 1.5-1.8 degrees below ‘normal’, and has been my whole life. Don’t know if that’s related.

        Conversely, even after all those years I take to southern heat like a duck to water. ‘Use it or lose it’ hasn’t happened for me at all.

        I think temperature acclimation is a worthy goal, and if it works for you, great. But my experience leads me to believe that it’s not always something one can control.

        • Gerard June 15, 2012, 7:46 am

          It’s probably worth splitting out endurance/toughness (how a lot of posters are interpreting all this) and the actual physiological adjustments that your body makes, if you let it — most of which, apparently, have to do with capillary blood flow near your skin. Karawynn, you’re good evidence of this — in effect, your body and bloodstream are permanently set to heat-loving! I hope that, long-term, FI lets you plan your life for comfort — a permanently warm climate, or summers north and winters south.

        • Clint June 15, 2012, 10:43 am

          Gom jabbar–from “Dune,” right? Great reference and very Mustachean connection what with the filtering-of-drinking-water-out-of-urine-and-sweat bit!

  • Scott June 14, 2012, 1:00 pm

    I built 365 linear feet of fence around my house in the worst of the Alabama heat last summer. I did save 75% off the lowest quote I got from a fence builder by doing it myself.

    But the heat didn’t have the same effect on me. I appreciated our air conditioner more than ever afterwards. I consider it a small triumph that I currently have our a/c set at 74 this summer instead of 72 like last summer.

    • Mr. Money Mustache June 14, 2012, 2:22 pm

      SEVENTY FOUR!!??!

      I guess that’s not so bad – if you adjust upwards by one degree a day, you’ll be at a reasonable setting in only 10 days.

      I think the reason you didn’t get the same benefits from working in the heat as I did is that you drowned it out with excessive A/C each night. The idea is to do these high-heat exercises, and then use the extra conditioning to allow you to make the rest of your life warmer as well, while remaining comfortable.

      • Scott June 14, 2012, 2:32 pm

        Well, I am only cooling 3400 sq ft. Ok. So I have some work to do. But I am super conservative with my money compared with my neighbors.

        • Mr. Money Mustache June 14, 2012, 3:09 pm


          Remember, you’re not in a competition with your neighbors any more – that would be too easy. You’re in a competition with the Mustachians.

          Mustachians, what temperature would YOU keep your 3400 square foot house at in the summmer, to keep A/C costs reasonable?


          • Llama June 14, 2012, 4:02 pm

            Stay downstairs and open the upstairs windows! Run a ceiling fan or pedastal fan right at you! Run a box fan IN one upstairs window and OUT another! And have an otterpop or 3!

          • Spencer June 14, 2012, 5:04 pm

            I wouldn’t even consider myself close to junior mustachian and I refuse to run AC for anything larger than 200 sq feet. If the weather gets ‘really’ bad, I find the most efficient room in the house, lock it up and throw in an efficient window AC unit (which I haul out from the attic). In our house, that happens to be a “theater room” which has only one window, a door to a finished garage (second coolest room in the house), no south or east facing sun-accessible walls and a double-wall structure (for sound deadening reasons). The sad part is that then we usually run a lot of heat-generating appliances (projector/speaker/receiver/player) for entertainment that fight against the AC unit so it has to work harder.

            I’d rather like to know how someone would even keep 3400 sq feet clean. I can’t even imagine.

          • Lavender June 14, 2012, 8:46 pm

            We have a 3000 sq ft. house, and have it at 80-82 degrees in the day, 77-78 at night. I’m thinking this summer’s challenge will be to raise those temps by a couple degrees…

          • bogart June 15, 2012, 8:14 am

            Well, I wouldn’t *have* a 3400 sq ft house unless one were foist upon me (and maybe not then), but I’ve resigned myself to our ~1600 sq ft one being no more than 78 if DH is home, and down to 76 or 74 for sleeping. The a/c is cheaper than the marriage counseling would be, never mind divorce.

  • ErikZ June 14, 2012, 1:00 pm

    I’ve been avoiding turning on the AC this year for several reasons. I’m surprised at how well I’ve been able to acclimate. It hasn’t gotten to the really hot nights yet though, and I’ve been running a window fan all night…

  • Mr. Frugal Toque June 14, 2012, 1:40 pm

    I guess I’m ahead of you on this one. I already did a 5k stroller pushing run and spent the last hour out weeding a flower bed and laying down landscaping fabric.
    Am I tougher now? Probably.

  • rjack June 14, 2012, 1:49 pm

    Does a similar process work for cold acclimation?

    • lecodecivil June 14, 2012, 5:42 pm

      Yes! When I was in college in the mountains of NC, during the winter we would have long stretches of highs in the 20’s. Of course when it’s 25-30 degrees outside, you bundle up and walk to class in the snow. But in the spring, when it hit 45? Shorts weather! Then I moved to Louisiana and think I need a jacket when it gets down to 50 in the “winter.” The cold acclimation might not be as scientifically demonstrable, maybe it’s just psychological, but it sure happened to everyone in the mountains.

    • Uncephalized June 14, 2012, 6:16 pm

      Yep. Your capillaries will move further away from your skin surface and your metabolism will also increase to maintain core temperature.

    • Julia K. June 14, 2012, 8:06 pm

      I haven’t found a way to acclimate to cold. :( I have great heat tolerance, but am typically uncomfortable below 74 degrees. I live in zone 7a (DC). The thing that worked best for me is buying some merino base layers (top and bottoms) and wearing them under my clothes October through March. I suppose I could, alternatively, put on tons of muscle or tons of fat, but…yeah, no.

      • Matt June 15, 2012, 3:20 am

        I live in the UK and we rarely see temperatures above 25’C, and even the 20’s isn’t common, so being cold is something, particularly the women folk, complain about a lot over here, but there is a “shortcut” you can do.
        You can cold acclimmatise very quickly, simply by having a cold shower first thing in the morning. It’s torturous for the first couple of days, but you soon get used tot it and it you certainly feel warm enough the rest of the day. You can do it slowly to by reducing the temperature of your hot shower a little each day instead though.
        And the added bonuses are, it wakes you up fully and you’re not paying for hot water.

        • Uncephalized June 15, 2012, 8:03 am

          Beat me to it! Cold showers really work. This is good advice.

          As a bonus, cold water is supposed to help with weight loss, too. It increases metabolism and doesn’t have as much of an appetite-boosting effect as exercise does.

    • Oh Yonghao September 19, 2014, 2:18 pm

      Yes, it works similarly. I noticed my first year in Taiwan starting in August the winter came and I was still in short sleeves and laughing at the natives with their eskimoish coats on. By the second winter I was one of those wearing a large jacket with a scarf and trying not to freeze.

      Now I’m back in the states. Started riding my bike in the winter and quickly acclimated to the cooler temperatures. Wearing layers and such helped, but I don’t have much problems with it being cooler. My wife has adapted slightly better, but a large part of cold seems to be knowing what to wear.

      When we went back to Taiwan we got a whooping due to the high humidity and heat that we weren’t used to. I’d say it does go both ways, but the cold is easier to handle with just adding more clothes. Part of it is psychological, like my wife “not liking” the cold. This year I think we’ll do even better with winter, but I may be convinced to bump our thermostat up to 67F from last years 65F.

  • Huck June 14, 2012, 1:55 pm

    Hey MMM…I’m wondering if you can EXPAND your temperature tolerance range or simply SHIFT it? I guess maybe it doesn’t matter if the body can SHIFT at a quicker rate than your surroundings can (you mentioned adaptation occurs within a week). If weather is the only factor then its possible the body can adapt to the low-ish frequency temp changes of nature. But is it possible for me to bike 15 miles home in 94 deg weather like I did yesterday and walk into that chilled out pub without needing a jacket? I like to believe I can (as you know, I wear shorts year round) but never found any scientific proof or tried to measure my own stats to see if my tolerance range is actually expanding.

    • Mr. Frugal Toque June 14, 2012, 2:21 pm

      Until I was relieved of the obligation a couple of weeks ago, I would bike to work in 33C weather, then take a very cold shower and spend the rest of the day working in a room that – due to poor engineering and climate control – was often at 19 to 21 degrees.
      I managed to adapt to the temperature swing.
      The only problems come when you have to repeatedly go through that temperature swing multiple times per hour. At a previous job, another climate control error caused large temperature swings while walking through one set of labs to another. This would cause headaches and other problems for a lot of people.

      • Debbie M June 14, 2012, 2:59 pm

        Interesting. And here I’ve been wearing hats and putting my hair up when outside, and wearing jackets and leaving my hair down while inside. I do try to last as long as I can before putting on my jacket when I come in and often take a while to remove my jacket and put my hair up when I go out, but I definitely don’t just pick one set of clothing and stick with it.

        I only change back and forth a couple of times a day. I’ll go to work and leave for lunch. Or maybe I’ll go several air-conditioned places on the weekend.

    • Mr. Money Mustache June 14, 2012, 2:23 pm

      Yeah, you CAN do double acclimation simultaneously, according to the reading I did before writing this post. Not too much use for it in a standard climate, but I suppose extra badassity is always fun.

  • win June 14, 2012, 2:01 pm

    From Walden:


    “Darwin, the naturalist, says of the inhabitants of Tierra del Fuego, that while his own party, who were well clothed and sitting close to a fire, were far from too warm, these naked savages, who were farther off, were observed, to his great surprise, “to be streaming with perspiration at undergoing such a roasting.” So, we are told, the New Hollander goes naked with impunity, while the European shivers in his clothes. Is it impossible to combine the hardiness of these savages with the intellectualness of the civilized man? According to Liebig, man’s body is a stove, and food the fuel which keeps up the internal combustion in the lungs. In cold weather we eat more, in warm less. “

  • win June 14, 2012, 2:06 pm

    No mention of humidity. Go to Virginia in August when it’s 95 degrees and 95 percent humidity. Turn off the AC and you will look like you just walked out of the sauna. My Dad loves this hot, humid weather, because he says it’s good for his arthritis. I just complain and threaten to move to California.

    MMM lives in a paradise of climate, low taxes, good public schools, etc.
    I’m moving to Longmont. :)

    • Mr. Money Mustache June 14, 2012, 2:45 pm

      It’s true that humidity raises the effective temperature.. but that doesn’t change the fact that you can improve your body’s ability to function in the higher temperatures. That’s the real point of this article – wherever you live, push your comfort limits to make them wider.

      One of the reasons the place I live sounds like a paradise, is because I make a point of talking mostly about good things. A complainy blogger could make this place sound much less fun by focusing on the plant-killing dryness, the short growing season due to freezing nights half of the year, the lack of international culture, oceans, or beaches.. probably many other things too.

      Virginia is better than Colorado in many of those departments, so I’d write about those if I lived there instead. It’s all about finding what’s good in your life and capitalizing on it. But I agree that moving is fun too.

      I just got the real estate report for Longmont – record improvements in average and median sales prices, drops in inventory, and very quick sales times. Are all the blog readers moving here secretly and causing this crazy spike? :-)

      • Matt June 14, 2012, 2:58 pm

        If there is a need for any manufacturing engineers or planners in your area let me know because I’m sick of the heat in Houston.

      • Jamesqf June 14, 2012, 6:13 pm

        “A complainy blogger could make this place sound much less fun by focusing on…”

        Not to mention the fires.

        • Mr. Money Mustache June 14, 2012, 6:37 pm

          Oh yeah! Now that you mention it, there IS a huge forest fire raging in the mountains nearby. One day last week the wind was just right and my whole city was buried in an eerie campfire-smelling fog of smoke. The fires don’t bother me though, even though I feel for the people whose houses burn down.

          • Jamesqf June 15, 2012, 2:51 pm

            Had one here back in January. Was evacuated for a couple of days. Didn’t lose much myself, but there were intense flames – enough to melt all the aluminum of my camper shell – within about 10 feet of the house.

            • Stubbily mustache June 16, 2012, 8:57 am

              I live in central Virginia, and haven’t used AC for the past several summers. Of course I also prefer the humidity and heat around that of Puerto Rico. Point being it can be done, and the temperature rarely gets above 80 even on the hot days.

      • bogart June 15, 2012, 8:20 am

        Yes, I’d always heard how much “better” the dry heat out west was but didn’t get out there until I was a young adult at which point I realized: I am a water-based lifeform. Man, is it hard to stay hydrated in the desert southwest.

  • LG June 14, 2012, 2:30 pm

    As a Phoenician who has not yet turned on the central air for the year, I think I am obliged to comment.

    This year we are doing a personal challenge of sorts to see how long we can resist expensive climate controlling. Our electric bill has been hovering at the $60-65 mark, for 350 kwh (that’s 30 in usage but also 30 in fees) and it is ever so much nicer than $200-300.

    Results so far: indoor temp is 95 when it is 105 outside. Night gets cooler but we can only get the house down to ~83 before the sun comes back up for the next day.

    Biggest achievement: We have not died or suffered too much yet, surprisingly. Your body just adapts. It’s awesome, I do light yard work in the middle of the day.

    Prediction: When the monsoons hit and the humidity rises (heat index soars), we will really be thinking hard on the a/c. Might turn on the one wall unit and sleep in that room. It’ll be a hard decision!

  • Norman June 14, 2012, 2:36 pm

    I grew up in Oklahoma without air conditioning. Either your body adjusts or you adjust. We were very used to living without a/c but there were some hot nights with high humidity where my brother and I would sleep in a tent outside for a good portion of the summer. My parents would take our only fan. My sister would mist her sheets so they would be cool when she climbed into bed. I remember being so thankful when there was a cool breeze blowing through the house. I enjoy having a/c now but I don’t keep it nearly as cold as most people I know. And like MMM, I hate walking into a store or restaurant where they have the a/c so low, its frigid.

  • Mr. Everyday Dollar June 14, 2012, 2:48 pm

    I am a long time yoga practitioner but last year i started doing hot yoga in a room where they crank the heat to 100+ degrees.

    The first few classes were a bit hard to adjust to and I even felt light headed sometimes, but then after a few weeks I adjusted – the human body is amazing! – and now I absolutely crave that heat and all the sweating that accompanies it.

    Mr. Everyday Dollar

  • Mr. Risky Startup June 14, 2012, 4:00 pm

    Funny that this post about building the fence comes right after the post about trust… ;)

    Heat is all relative. In the summer months, we would spend our time eating ice cream to keep cool. Yet, many people in Middle East actually drink hot tea to keep cool. I used to laugh, but then I tried it and it works – by warming up your body, outside temperature feels cooler.

  • lurker June 14, 2012, 4:04 pm

    i have noticed the same thing now that I try to bike for an hour or so most days. My body seems to be adjusting well to the seasons and I am much more comfortable than before. perhaps losing weight and being in much better shape helps in that department as well.
    cheers to all. stay cool and hydrated!

  • Dragline June 14, 2012, 4:39 pm

    Lest some might think this is mostly in your head, here is a recent article with summary of the science behind it:


  • Erica June 14, 2012, 4:42 pm

    Whatever you do, you cannot forget to stay properly hydrated. As an Arizona native and someone more accustom to the heat it’s easy to not realize you still need to be drinking more when you’re exposed to extreme heat.

    Just last week the power on the whole block went out, and I spent time outside getting fresh air and eventually made my way to the local mall. I drank a fair amount (I think somewhere around 140oz), I thought, but ended up suffering from heat stroke. The heat hit a blistering 109 degrees, but I didn’t feel anything at first. When I got home after power was restored it seemed to hit me like a wall. It was the most painful and most terrifying experience of my life.

    I’m not saying don’t do this, because as a native who went back east for college and managed to adjust there as well, this definitely works well. Just be safe, stay hydrated and know your limits.

    • Mr. Money Mustache June 14, 2012, 6:40 pm

      Good point – I somehow erased my part about drinking water in the article, so I’ll go add that back in right now..

    • Jaketucson June 15, 2012, 9:04 am

      As a 30-year AZ dweller myself I’ll add that in really extreme heat like we have here, sometimes plain water isn’t enough. Diluting gatorade (or another sports drink) half-and-half with water can help a lot. Or even just putting a small pinch of salt in your water (not enough to change the taste much). Don’t know if this is equally helpful in humid environments but I would guess that it could be.

      FYI Erica, could be 140 oz of plain water threw off your electrolyte balance. That’s over a gallon of water in what sounds like a short-ish time span. I’m not a doctor, but I’m a trained firefighter/EMT as well as a long-distance runner and that is a lot of water even for me when I’m exerting myself. I certainly agree with the “know your limits” statement.

      • Aja November 10, 2013, 9:01 pm

        I agree. I live in a hot dry climate and need a Gatorade-type drink almost every day in the summer, even after acclimating. In hot developing countries aid agencies pass out measuring spoons to make your own cheap homemade version with water, a big scoop of sugar, and a little scoop of salt. I prefer to make mine with either lime juice or cashew juice concentrate. Google offers lots of recipes online. I live with no climate control except a small space heater for really cold nights (single digits celcius/low 40s F, and a drafty apartment) and 40C/100+F summers, so helping my body adapt seasonally is key.

  • Matt June 14, 2012, 5:10 pm

    Does anyone wake up in a sweat-soaked bed every morning? That’s the most annoying thing about keeping the AC off. Sometimes I will rotate a towel under my body during the night, but it is pretty uncomfortable to roll around in a puddle all night. The same is true if I work on my laptop in 1 place on the couch for too long.

    I thought about getting some sort of hammock or mesh furniture, but haven’t yet.

    • Jamesqf June 14, 2012, 6:20 pm

      That’s not necessarily due to heat, but can be a symptom of a number of diseases, or a side effect of some medicines. Aspirin is a very common one. Do a search on “night sweats” for more info.

    • Marcia @Frugal Healthy Simple June 14, 2012, 6:33 pm

      Yes. But I’m pregnant.

    • Spencer June 15, 2012, 1:42 pm

      If I find myself sweating at night, I’ll grab a hand towel, get it wet and lay it on my chest, arm or back. Double that up with a small fan (even a desk fan works) and you’ve got a mini swamp cooler right on your skin. You shouldn’t need it to cover too much area, just having a small area cooled seems to do wonder. Obviously if you’re in a fairly humid area, the efficiency can drop drastically. It’s pretty dry in my part of the world.

    • SweatingMyBallsOff June 25, 2015, 12:21 pm

      Yep, nights are the problem. I turn the AC off when I wake up; when I get home it’s usually over 90F inside. Then after walking the dog its time to crank up the unit. Surprisingly, my bill never goes over $60. In fact, it costs more to heat my house in the winter… even setting the heat to 60F or less AND THIS IS FLORIDA! Speaking of which, didn’t MMM in an earlier post carve out an exception? “About a quarter of this country suffers through summers with unbearable heat and humidity.” Anyway my place is relatively new and well insulated, and at only 640 sq. ft. I can justify the late June ‘meat locker’ nighttime setting.

  • Sergey June 14, 2012, 5:13 pm

    Nice! I gradually got used to be comfortable when the inside temperature is between 64 and 80. Could have tried a bigger range but my gf always complains.

    Also, have been driving a car without ever turning on AC this year. All in humid and pretty hot state of Nebraska.

  • George June 14, 2012, 6:08 pm

    I know I am definitely used to the heat. I love being outside in the middle of summer during the afternoons while others stay inside staying they can’t bear it.

    One thing that helps is whenever you know you are going to be in a public building, i.e. a doctor’s office or grocery store, for awhile, I always bring an emergency backup long-sleeve shirt or sweater so that I don’t freeze too much in the Summer. Grocery stores, in particular, like to make their interior feel like a frozen arctic ice box (probably to help keep the food cold), while some places just love to jack up the AC.

    Before you bike out from home, always remember to bring that long-sleeve shirt just in case. It is really interesting that MMM has actually figured out the science behind actually adapting your body to temperature.

  • EJ June 14, 2012, 6:15 pm

    MMM – Are you going to stain that fence? I just put up 168 lineal feet of 6 foot privacy and wondering how long I need to wait to stain it. I’m hoping to spray on a clear stain sometime this summer to keep the beauty in the wood.

    • Mr. Money Mustache June 14, 2012, 6:34 pm

      It IS already stained in the picture! I used the Behr 6-year transparent stuff in “cedar naturaltone”. The wood was much lighter and more yellow before staining. I do find that outdoor wood lasts many times longer if you re-stain it every 5 years or so.. plus it looks nicer to me.

      • Matt June 15, 2012, 7:49 am

        All the A/C talk aside, the fence is badass! I love how it intertwines with the tree great job!

  • Jay June 14, 2012, 8:38 pm

    MMM, what are you going to do with the fence as the tree grows?

    Hell with your huge privacy fence, now you can do the ultimate in mustachism and run around naked to be even cooler.

    • Mr. Money Mustache June 14, 2012, 9:10 pm

      I suppose I’ll trim or replace the boards which touch the tree every few years. Probably less than 5 minutes per year of work on average, which seemed like a reasonable cost to add a sort of J.R.R. Tolkien feel to that part of my yard.

  • Entity325 June 14, 2012, 9:46 pm

    Colorado dirt is rock-hard? I just figured digging was hard work. Granted, I’ve never dug more than a couple of post holes at a time…

    Wait, electric-powered dirt auger?


    I wear a T-shirt and jeans for about 80-90% of the year. It’s good enough for me anywhere from 100 degrees all the way down to 20 F as long as there’s no wind.

  • JamesAt15 June 14, 2012, 10:46 pm

    Dammit, MMM called me out before I had even got to the slacking off part…

    I have been biking to work frequently in recent weeks, about 18km each way, but was expecting to wimp out when the rains start up (rainy season) and then the 30C high-humidity Tokyo summers kick in immediately afterwards (i.e. summertime).

    Now I would feel like a real wuss…

  • Joe @ Retire By 40 June 15, 2012, 8:21 am

    We live in the Pacific Northwest and our climate is cool in general. We used to be able to endure the heat a lot better when we lived in CA.It just take time to get acclimate and we don’t have enough hot weather for that. Oh well…
    Also, now when I visit a tropical country like Thailand, it is so much more harder than when I was younger. The heat is just too much for a short 1-2 weeks visit.

  • JaneMD June 15, 2012, 9:12 am

    Our apartment a/c is set to at 78 degrees. I have energy efficient windows and the energy efficient curtains, but it still isn’t cheap. I keep the a/c off until I feel ‘warm’ at about 83 degrees. Then I turn the a/c on till I feel ‘cooler’ at about 79 degrees and then I turn it off.

    I, unfortunately, am limited because my apartment controls the thermostat and shares the electric bill with the upstairs apartment. We’re about 1800 feet, and I believe its 700 feet up there. The bill is split 60:40 because the upstairs apartment is utilities included by the landlord. So no matter how motivated I am to minimize AC use, the upstairs person is not financially motivated. They do have a windown unit up there, so if they hate my AC management, they can turn it on. It will still be less than the central AC.

    Yes, the two apartments used 2200 kwh in 31 days. I can only imagine what it would be if we ran the AC continuously.

  • TrekMan June 15, 2012, 9:45 am

    MMM, how do you plan to categorize the expense of putting up the fence? For example, would this be considered an investment because it may raise the value of your house or would you consider it an expense because its primary function is to make your back yard more fun to hang out in? If I think back on Jacob’s ERE site, he’d call it an expense.

    My wife and I have been doing a lot of home rehab for the past two years on our place and I’ve always considered it an expense rather than investment. We do almost all of the work ourselves, we’ve only had to have an electrician come once.

    • cdub June 15, 2012, 9:49 am

      It is an expense either way. He may be able to keep track of the expense and use it for tax basis something or other (sorry, my accountant has me keep track of all home improvement maintenance costs) when he sells the house. Anyway, it is an expense.

    • Gina Johnson August 25, 2013, 11:16 am

      It depends. My husband builds fences for a living here in Texas. If the fence is cedar board on board, it tends to raise the property value, so it can be viewed as an investment, at least partly. If its side by side, no benefit other than not *lowering* the property value by having a shabby fence.

  • cdub June 15, 2012, 9:47 am

    We are fortunate to have a nice “delta breeze” most evenings in Sacramento so we are able to keep the AC off and the windows open.

    Here is the weird thing for me. I don’t mind being hot when exercising or doing yard work but I cannot stand being hot while at work or otherwise “idle at a desk trying to concentrate.” When working from home as a consultant, I would go insane trying to concentrate when the AC was out on a 100 degree day. I would actually drive (Can’t bike, might have got a client call that I need to respond to immediately in a far away land) to a coffee shop just so I could get some work done.

    I would love to move someplace in the Pacific North West but my wife is not too hot (he he) on the idea.

  • win June 15, 2012, 9:57 am

    My California relatives have a swamp cooler. They said it was cheap to run and it really cooled the house.


    “In the Arizona desert in the 1920s, people would often sleep outside on screened-in sleeping porches during the summer. On hot nights, bed sheets or blankets soaked in water would be hung inside of the screens. Whirling electric fans would pull the night air through the moist cloth to cool the room.

    That concept, slightly more refined, became the evaporative coolers that to this day provide a low-cost, low-technology alternative to refrigerated air conditioning.

    An evaporative cooler produces effective cooling by combining a natural process – water evaporation – with a simple, reliable air-moving system. Fresh outside air is pulled through moist pads where it is cooled by evaporation and circulated through a house or building by a large blower. As this happens, the temperature of the outside air can be lowered as much as 30 degrees.”

    • Jaketucson June 15, 2012, 1:27 pm

      +1 on swamp cooler. Many older houses in AZ have these. I don’t know why new houses aren’t built with them as frequently anymore. They are very cheap compared to A/C, can be maintained very easily by the homeowner and do a great job cooling. You also have to have at least 1 window cracked a bit for it to work well, meaning you’re getting fresh air exchange in your house. Plus, it puts some moisture into the air that an A/C would just suck out. The only drawback in AZ is July-Aug it gets really humid here during the summer monsoon season and they don’t work as well.

  • sideways8 June 15, 2012, 10:14 am

    I’m mildly uncomfortably cold at work right now and the temperature is set at 74. The other side of the building is even colder. It’s only been in the 70s-80s this week so I’ve actually had to bust out a blanket for couch time!

  • win June 15, 2012, 10:40 am

    Ceiling fans are cheap on craigslist and make a room much more comfortable.

  • Matt June 15, 2012, 10:51 am

    Someone I used to work with told me about this same heat adaptation. He’d go for a run every day around noon. This is in central Illinois, where, in the summer, we have 100 degree days plus crazy humidity. I asked him how he managed, and he basically described the body’s natural adaptive ability that MMM just did.

    I’m with some of the other posters, in that I find heat pretty easy to adapt to, but I struggle with the cold. I have about a 10 minute walk to the train every day, and on the single-digit and below days, it just never gets any easier. The wind is truly painful when it cuts into what little bare skin I have exposed.

    Anyway, MMM said, “If you carefully and gradually push your comfort boundaries, just as with any form of other exercise or badassity training, you tend to extend those boundaries in a positive way.” I think that’s a general useful strategy for life overall (not just achieving FI). I get the feeling that many people really can’t imagine stepping out of the comfort zone for even a brief amount of time… but it’s really the only way to grow. And I’ve discovered what appears to be a paradox: in some cases, that temporary, self-induced step out of comfort actually becomes enjoyable. In particular, for me, it’s strength training. It’s definitely not comfortable to shoulder a heavy barbell, yet it’s something I enjoy. And when I’m done I feel fantastic.

    I think the idea of regularly and deliberately experiencing some mild discomfort is a fundamental underpinning of Mustachianism. It’s really the exact opposite of hedonistic adaptation.

  • CrucialDebtCrusher June 15, 2012, 12:17 pm

    I made the 20 miles to work today, I feel unstoppable. Eating my self-made sandwich to restore the energy for the evening ride back.

    Make no mistake, the first full run was tough. I felt weak and slow, and in unfamiliar territory. Then, some old guy passes me and I realize that I’m un-acclimated, remembering that I must be badass.

    Face punches work.

  • Posted On June 15, 2012, 12:21 pm

    “These guys would often work alongside me on searing-hot days in black jeans and long-sleeved Denver Broncos sweatshirts, while I could barely survive with a white t-shirt”

    I’d always heard that long-sleeves and long pants keep the sun off as much skin as possible. This can be key for staying cool when out and about on sunny days.

    • Mr. Money Mustache June 15, 2012, 2:48 pm

      That’s true – later I found out that long-sleeved super lightweight white shirt with a collar was ideal. Even as a white dude, my skin is much darker than light fabric in the summer, meaning it absorbs a lot of unnecessary solar heat. Light colored khaki or cargo pants are a good combo for this.

      The thing about the concrete workers is that they were so tough they could ignore things like breathable fabric or light colors. Just their regular black work jeans were fine for them.

      • Greg June 15, 2012, 3:59 pm

        My great-grandfather was a farmer and always wore long sleeve shirts to work in with the top button buttoned.

        • anna January 8, 2014, 3:58 pm

          I live on a little island not too far from the equator (off the northern tip of eastern Australia), and when I am going to be outside for long periods (and not having the benefit of natural enhanced sun protection like much of the local population) I use shirts I picked up at a camping/outdoors store that have SPF50 (I think, from memory)They are super lightweight, have vents etc so they are not too hot, despite being long sleeved with collars.

          When it is really hot I put a bamboo or other quick drying singlet on underneath, button the top couple of buttons and have the collar up, so the body of the shirt is loose around me and circulates to evaporate sweat and keep me cool. This means the bits that are prone to sunburn (back of the neck, shoulders, chest) are protected, but I am still cool. I usually top this off with a sombrero style hat of course. This method has worked well for me for outdoor diy projects with lots of sun exposure (e.g., fence painting) as well as long fishing trips in the beautiful torres strait (don’t hate me).

          At the risk of this becoming a v long comment (sorry), I am a reformed whinypants regarding the heat, and I completely concur with MMM that acclimation can occur very quickly. My parents came up to visit recently (from a cooler part of Australia) and were melting, whilst I was running around turning off the a/c because I was too cold. I have only lived up here a couple of months.

  • James June 15, 2012, 12:57 pm

    As a hairy man, I find it helpful to trim/shave a lot of my body hair in the summer. This makes being hot and sweaty a lot more comfortable during the acclimatization period.

    To those wondering about cold-weather acclimatization, think about investing in some sort of thin-shelled down coat or jacket. They are incredibly light and incredibly warm. I wear mine around the house when I want to keep the temperature as low as possible. That’s why I prefer the cold; unlike in hot weather, where you can only get so naked, cold weather is easy because you can always put more layers on.

  • catalana June 15, 2012, 1:08 pm

    Totally agree that you can acclimatise – and that you don’t need to tackle it in the extreme way that MMM did. Simply be active outdoors right throughout the year, and it should never be too much shock to the system.

    I’m in a cold (UK) climate, and walk 1.5 miles home from work right through the year, which means low 30s for several months of winter. I would hate that walk if I suddenly had to do it after taking the bus every day, but because I have done it every week as the temperature drops during autumn then I can cope.

    I do agree however that there is only so far you can push your boundaries. In the evening I struggle to stay warm in the house compared to my fiance. Thermal underwear and blankets in the lounge is the order of the day! He just naturally runs warmer than me.

    In hot weather I find life easier though!

  • Honey Smith June 15, 2012, 2:20 pm

    I live in Phoenix, and just started biking to work this week (for the first time since moving to Phoenix, that is). I recognized my “I will wait until October” to start doing this as procrastination that would cost me almost 4 months’ worth of savings! Incentive: if I can get through July without using my car, there’s NO REASON I can’t do it year round.

    • Mr. Money Mustache June 15, 2012, 2:45 pm

      Excellent Honeysmith, that is Super Hardcore! You are making us Coloradans look like wimps. Phoenix is really a shining beacon for the whole world, actually, because it makes it so nobody else has an excuse to complain about summer heat.

    • Oh Yonghao September 19, 2014, 3:38 pm

      That’s the same logic I used for starting to ride in January near Portland, OR. If I can make it through winter I can ride year round. Way to go!

  • Jamesqf June 15, 2012, 2:59 pm

    Something else to think about, if you run or exercise with your dog, is that s/he probably can’t adapt to the same degree of heat as you can, especially if they are of the more northern breeds. On the other hand, they’ll be quite happy lying in a snowdrift, or wading in an ice-rimmed stream.

  • Robin June 15, 2012, 4:05 pm

    I was wondering why a high of -20 degrees didn’t seem so bad after living in MN for a few years. I’m going to try and take the no a/c challenge this summer. The hardest part is going to be keeping the husband away from the thermostat. He agrees with my mustachian ways but has some trouble with the follow through.

    I think I’m acclimated to the heat more than him since I’m from the South and he’s not. I play roller derby and skate outside during the summer a lot which builds up my tolerance as well.

    When it was in the 90s the past few weeks we used frozen 2 liters in front of a fan to create inexpensive a/c. A medium tabletop fan only uses about $10 worth of electricity a month (measured our with a kill-a-watt device). We keep several 2 liters in our freezer that we swap out. Keeping your freezer full actually uses less energy. I’d like to think we break even but I haven’t measure that yet.

    We also signed up for “Savers Switch” with Xcel energy. It’s this device that attaches to your central a/c unit which turns the a/c on and off every 20 minutes for just a few hot days during the summer. We get a 15% discount every month June-September every year for participating. If we use no a/c, then we still receive the discount! I’m liking the idea of saving money by pairing little to no a/c usage and the 15% discount!

  • Eric June 15, 2012, 10:58 pm

    Great point. There are also a lot of efficient ways to retrofit your house to either use less energy to maintain temperature in a given range, or to have a more comfortable home without AC. I installed a radiant barrier in my attic last year (ok, so I actually paid someone else to do the work, which was admittedly non-mustachian of me, but it was before I discovered this blog). I haven’t run my ac all year (I live in north Carolina) — it’s 81 degrees in my house, I have the ceiling fan on low, and I’m feeling fine. My electric bill is down 30-50% since the installation. Tomorrow, I’m picking up someone’s discarded concrete footers to add some thermal mass to my house.

  • N June 16, 2012, 6:05 am

    I live in a hot (over 43C/ 110F every day this week) humid climate and our landlord has told us to never have the AC set at less than 24 C/ 75 C because the mold will take over at hotter temperatures. We’re not wussypants over here – we bike to work and back every day and we’re fine. But apparently our house can’t handle the heat. Any recommendations?

    Also, I’m another one that cannot do cold at all. I can go for a perfectly good run when it’s over 90 F (at 10 pm!), but my hands lose all circulation at around 65F.

    • Jim October 4, 2016, 7:52 am

      This is an old article, but your landlord could be correct depending on what part of the world that you live in. The author is able to do this because he lives where humidity isn’t a great concern, but if it is a concern than not removing humidity will not only cause mold, but can aggravate or cause problems in people with “weaker” respiratory systems… asthma, allergies, etc and could cost more in home repairs than the electricity savings.

      The good news is that you can deal with these problems, but it will take some effort. The first step is not to think of an air conditioner as a cooling appliance, but as a dehumidifier that provides cooler air as a “waste product.” Once you measure the humidity load inside over time, then all you have to do is run the system enough to remove that humidity. It will not take much energy if your system is tuned for this purpose, but that’s not common. There are many variables, but it’s possible to remove even high humidity levels in about 20 minutes of system run time per 24 hour period. You really have to understand the concept of a psychrometric chart to gain maximum benefit.

      One problem is that some energy efficient systems sacrifice de-humidification for a faster temperature drop to meet those standards which is actually counter-productive and largely misunderstood. Depending on who and how the system was designed and installed can make this much worse. Tweaking an air-handler for maximum humidity removal is beyond the scope of many, but it is worth the time and savings if you are willing to dig into it. A humidistat controlled system isn’t always an efficient way to handle this problem.

      One thing to understand is that you can actually feel more comfortable at a higher temperature and lower humidity than you would at a lower temperature and higher humidity which might be a hard concept to grasp, but you can use to your advantage. You can’t compare just outdoor temperatures at different locations in the US, but it is still done because it easy to understand and no one likes talking thermodynamics. Look up dry/wet bulb temperatures as a starting point.

      The major problem with high humidity is not body acclimation, but as an extreme case I know someone that never uses heating or cooling systems that lives in a humid area, and he has accepted the fact that he cannot keep books or papers for more than a few weeks, and clothes, etc, need to be stored in airtight bins after washing because the humidity is high for most of the year. The unchecked humidity levels inside his home cause his clothes to smell, and any thing that can absorb moisture, like paper will be ruined. That’s the reality of humidity in certain parts of the world that this blog doesn’t apply to.

  • Erik June 16, 2012, 10:11 am

    Another method of reducing heating and cooling costs is heat/cool only a small part of your home.

    This is what Minnesota farm families often used to do. They’d seal off a few rooms in the winter and keep those nice and warm, but the rest of the home would drop down into the 40s or 50s.


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