Where I live in Arizona it’s already getting hot with triple digit weather coming at us next week. Air conditioning (A/C) is pretty much a necessity in the desert and power bills of $200 to even $400 are all too common. What can we do to keep our houses cooler and use less of the A/C so that we can save energy and money? No, I’m not going to say, sell your house and build an earth ship or get a home that is actually designed to stay cool with passive cooling, thermal mass, etc. That would be nice in an ideal world, but most of us are already in conventional homes. Our styrofoam and stucco outer walls are built as cheaply as possible and designed by a developer that didn’t care much about how energy efficient the home was. If we were smart (or lucky) we at least bought a home that was orientated advantageously, with the long part of the house facing north and south. This orientation allows for the most shading of the house during those long, hot summer days as long as the roof hangs over enough to shade the south.
Also if we were smart (or lucky) we bought a house with a minimal number of windows on the east and west sides, where the morning and late afternoon sun can penetrate deeply into a house. In the picture above you can see the late afternoon sun flooding this house with heat. Here is an example of how orientation makes a difference. The City of Davis California conducted a study where for one year, 
they took readings from minimum and maximum thermometers inside the unoccupied units of two identical 2-story apartment buildings with one difference, one was orientated with the long walls on the north and south and the other east and west, the north south apartment stayed 24 degrees cooler in the summer, and 17 degrees warmer in the winter. This was done without the use of A/C or heating, Wow! If you are moving or looking for a house this is important to keep in mind.
Okay, so most of us aren’t house shopping and are already in our houses. We’re not moving anytime soon so we have to work with what we have. Here are some tips for doing that.
- Windows account for 1/2 of a home’s summer temperature increase. Install white mini-blinds or shutters and keep them closed when the sun is hitting the glass. These can reduce solar gain by 40% - 50%.
- If you have curtains close them on windows that receive direct sunlight.
- Install awnings on south facing widows if the roof overhang doesn’t block all the sunlight from reaching the windows.
Install sunscreens on the exterior of windows that receive direct sunlight to block sun from reaching the glass. These block as much as 60% - 80% of the sun’s heat from reaching the glass. Get a few quotes from licensed contractors, prices can vary quite a bit.
- If your HOA won’t let you do sunscreens or awning or they cost too much money, you can apply Heat Control Window Film
on the glass to reflect much of the heat from direct sunlight. Heat control film is relatively inexpensive and reflects much of the sun’s heat.
- Check windows and door frames for any hot air leaking in and seal them with caulk or weather striping.
- Plant shade trees along the north, east, and west sides of the house to shade it from direct sunlight.
- If your house needs to be painted choose lighter colors that will reflect more heat. HOAs usually forbid certain colors, so check with them first.
- Use Compact Fluorescent Light bulbs (CFLs) inside. CFLs use 75% less energy and produce 75% less heat than incandescent light bulbs which saves on cooling costs.
Set the thermostat to as high as you can tolerate. According to the SRP’s web page every degree over 80 saves you 2-3% on cooling costs.
- Use ceiling fans or other fans to circulate air in your house. This helps you feel cooler so you can put the thermostat higher.
- Replace or clean your A/C’s intake filter once a month to allow for greater airflow.
- Use a microwave, toaster oven, stove-top or counter top grills instead of the oven during the day. The heat produced by the oven makes the A/C work harder to cool the house. You could also try a solar oven or grill and cook outside. Here are some plans for making your own solar oven very inexpensively. [solarcooking.org]
- Turn on the exhaust fan in your bathroom when taking a hot shower. This removes much of the humid air produced by the shower. As you probably know humidity makes it feel warmer.
- If it’s still cool enough at night, usually 77 degrees or less, open your windows to vent the house. Close them up in the morning to seal in the cool air. When we do this at my house the A/C usually doesn’t kick on until late afternoon. Using some sort of window fan can help bring in the cool air.
- Have your A/C serviced once a year to make sure it’s running at it’s peak efficiency.
Keep your A/C’s condensing unit shaded to help it run more efficiently, but more importantly make sure it has plenty of airflow. The condenser in the picture to the right could use some shade from a tree or bushes
- Install a Solar Attic Fan
to vent your house’s attic. If your attic gets hotter than the peak outdoor temperature, an attic fan can vent this extra heat and save you money on cooling costs.
- Upgrade the insulation in your attic. SRP has a good FAQ on whether you might benefit from more attic insulation [here].
- Install solar panels. This will cost a lot up front if you buy them outright, but after a few years they’ll pay themselves off. Leasing panels is another option. Your electric bill will be much lower for the life of the panels which is up to 30 years or so.
What else can we do to keep cool in the summer and save some energy? Leave a comment and let us know.
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James Towner | Posted in 
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May 14th, 2008 at 2:31 pm
Good info! Our kitchen area has 12 can lights each at 65W! It’s like standing under a heat lamp with them all on at once. We are definitely going to switch those to CFLs once they start to die out.
May 15th, 2008 at 10:17 am
No! Don’t use CFLs… Use LEDs! They last up to 11 years and produce less heat!
May 15th, 2008 at 5:04 pm
The sunscreens made a big difference after I had them installed. Actually, they do such a good job that you should remove them in the winter so the house can warm up with the suns help.
I’m planning on trying out the Cool-N-Save (Google it) system which uses a mister to help cool your condensing unit when it is in use. I also have the Power-Save 1200 (also Google it) on my wish-list which is a $300 module you install on your main electric panel that helps your power factor and thus helps your appliances and AC run more efficiently - which in turn helps lower your electricity bill.
May 15th, 2008 at 7:23 pm
I’ve heard bad things about the condenser misters. They work well at first but since there are so many minerals in our water it eventually builds up on the fins of the condenser and makes it run very inefficiently or even breaks the condenser all together. So be careful with that one.
May 15th, 2008 at 8:21 pm
And if you can’t sleep for the heat at night - get your thyroid checked. It sounds weird, but the thyroid plays a big part in temperature tolerance.
May 15th, 2008 at 8:38 pm
This is an awesome article.
I am heading to Home Depot to get some weather stripping for the doors.
I am also going to look into some sun screens.
I have added a link to this article on my blog as well as adding this url in my linkblog.
Again, awesome story!
May 16th, 2008 at 5:10 pm
Fabulous blog! I ran across one of your posts on Digg today, and was so excited to see something local.
Here’s my dilemma: It just got hot enough that we need to turn on the AC. We don’t have an evap cooler, so that’s not really an option. We’re on the 9pm-9am off-peak plan through APS, and we’re trying to figure out the most energy-efficient way to cool the house.
Is it better to turn it on really low between 9 and 9 and then turn it off, or is it better to keep it on all day, but with the thermostat at 80 or above.
My husband and I are at work most of the day, and we’re pretty tolerant of warm-ish temperatures. I’m looking to save energy (and money!)- what have you all found to be the best?
Thanks!
May 16th, 2008 at 7:59 pm
Thanks Elizabeth! I’m glad you found the site. You might have to play around a bit with the temps, but I probably wouldn’t totally turn it off during the day depending on how hot it gets in your house. SRP suggests setting your a/c to anywhere from 5 to 10 degrees above what you have it set to when you are home. At my house we usually set it to around 87 when we’re not home. Typically during the day when we are home it is set at 82 and then around 78 when we’re sleeping. We’ve been in this house for about 4 years and have never had a bill above $200. Also if you have critters around the house you don’t want it getting too hot. You kind of have to play around and see what works best for you and try to employ some of the tips from this post to help keep things a bit cooler. I hope you keep coming back and checking out the site!
May 27th, 2008 at 5:32 pm
The attic fan is actually one of the most common scams people buy into in the guises of saving energy. A solar powered attic fan cannot ever move enough air to cool down the average volume of hot (140-160F) air in an attic. The goal initially seems valid but in practice it never really works out.
The biggest problem with attic fans is the volume of air they would need to move to actually cool the attic in a way that would help. Note: I said ‘way that would help.’ When you install a high-powered attic fan it will actually slightly depressurize the house and suck COOL air that you paid for right up into that hot attic! That conditioned air has to be replaced by hot and humid air from the outside making the situation worse. I can’t tell you how many attic hatches I’ve stood in and felt the air rushing up through (or heard it through closed hatches and pull-down stairs.)
If you really want to help deal with the heat in the attic, just add more insulation. Increase the R-value of what’s up there and DON’T compact it with your belongings. Attics are not designed to store items. Insulation only works when fluffy.
Interestingly enough, the time you really want an attic fan is in the winter. It should be on a humidistat instead of a thermostat. Attic ventilation is intended to prevent humidity from condensing on the underside of the roof and ruining the plywood. In the winter, the first cold surface humidity (generated by the occupants) hits is the roof.
As for the PowerSave 1200, it isn’t going to help your power consumption one bit (Sorry). It is a bank of capacitors put in shunt across the power meter to correct the largely inductive loads in a home. Items with motors (Fridge, A/C) are very inductive and by adding capacitance, the PowerSave 1200 intends to bring the power factor back to 1.0. Power factor is the ratio between real and reactive power representing the ‘misalignment’ of the current and voltage waveforms. Fortunately, the power meter measures only REAL power and residential users don’t pay for reactive power. Big users like universities and commercial buildings will be charged for reactive power. Virginia Tech has a power plant on campus that they use for power factor correction. When you consume many thousands of amps, the power company cares enough to bother.
So, the best bets for your home would be increasing insulation to recommended R-values, sealing air leaks, and reducing humidity. If you absolutely MUST have an attic fan, here’s a quick trick to stop air loss: Buy a roll of pink insulation and two cheap bedsheets. Roll out the insulation several strips wide (enough to cover your hatch or pull-down stair) over the first sheet then lay the second sheet on top of it. Just staple the edges shut and cover your attic hatch! Quick, cheap, simple, and no itchy insulation down your shirt!
Best of luck and keep cool! Cheers!
June 11th, 2008 at 11:01 am
We too live in AZ and are always looking for ways to avoid the high summer bills. We just got sunscreens installed on our house and are looking forward to our first bills to see if there is difference.
My question is this, we have a 2 story home and we were lckyto get a north / south. The first floor is formal living, kitchen, office and great room. We mainly live on the second floor. Familyroom and bedrooms. We keep the top a/c at 83′ durning day and 78′ for sleeping. Downstairs is usually keep at 85′ or so. My wife thinks all units should be on 83′ durning day as heat rises. I say why cool an unused floor. any advise is welcome.
Thanks in advance.
June 11th, 2008 at 11:03 am
just noticed my wifes name is saved on her computer. Sorry, this is Rick.
Thanks again,
June 17th, 2008 at 8:20 pm
IS IT NORMAL FOR THE A/C TO RUN ALL DAY WHEN TEMPERATURES ARE IN THE 112-113 DEGREE RANGE AND THE THERMOSTAT IS SET AT 83 DEGREES INDOORS FOR A 2 STORY HOUSE WITH 1 A/C?
June 18th, 2008 at 10:37 am
To be honest I’m not too familiar with the best method for cooling a 2 story house. I know it can be a challenge to keep the 2nd floor cool since the cool air sinks and the hot air rises. I’d think you’d want to keep upstairs doors closed to trap in the heat. Now that it is 110+ degrees outside we keep our A/C on all day at 82 degrees and use ceiling fans. It is pretty comfortable like that right now.
June 30th, 2008 at 11:08 am
I have Evap and A/C but the evap is starting to not cut it. My system is set up so that I could actually have both on at the same time. Never tried it, but should I? Pro: Evap cools air cheaper and pumps into house to help A/C? Cons: A/C has to work harder to get rid of the humid air? What do you think?
July 2nd, 2008 at 6:54 am
Great article, I loved the info on the study about a house’s orientation north-south vs. east-west in regards to its temperature. Do you know if there are any studies or specific research done on how much an oven can raise the temperature of a house? I live with someone who really doesn’t seem to believe that it is better to make dinners that are cold rather than cooked in the summer to keep our apartment cooler. I want to site some numbers and research to her so she truly understands this point. Many thanks, Hazel
July 7th, 2008 at 9:16 am
We installed a whole house fan. When the air is cool outside (in the early morning and at night) we open windows 6 - 12 inches through out the house. We turn the fan on and it pulls the cold air in and draws it up thru the attic and out the vents. At the time our house was being built we had extra vents installed - 6 total. We can get the temperature of the second floor of our house down to 72 degrees depending on how long we run it for, we close it up during the day and this helps keep the temperature down. We set our ac at 82 and it hardly runs making our electricity bill reasonable. The only downfall that we can see with the whole house fan is the noise and dust. It is very noisy and when it is running and it also pulls in the dust. This is a small price to pay since it works so well.
July 8th, 2008 at 2:55 pm
If you are an SRP customer, you can go to participating Ace Hardware Stores and recieve 20% off on Sun Screens.
August 11th, 2008 at 8:30 pm
Thanks for this article. Any advice on what type of flooring is best to keep the house cool. Light colors make sense, but what about materials?
October 16th, 2008 at 7:13 pm
Agisman and many others who have labeled “power optimization” fraudulent, do not do good service to those who seek information. I have tested a Kvar unit, applied meters on a motor/Kvar connection and saw with my own eyes a drop in wasted energy. We applied the testing in a home in Arizona and found a monthly savings of 16%. This technology works on all inductive loads, period. Savings are scaled to demand. Do not listen to the voices that are connected to brains that do not investigate before commenting. Only listen to those with “practical” knowledge. Remember, according to the best engineers in the world…, a bumble bee cannot fly!!
March 29th, 2009 at 7:52 pm
thanx for the info i used some of it on a skul project
April 21st, 2009 at 1:29 am
My Yuma AZ home was built in the 50s. The house is a standard small three bedroom ranch, flat roof, concrete slab foundation with an addition. (The cartport area was converted over 30 years ago to room.) We have a full overhang roof along the north side of the structure that extends over a patio which is about 12 ft. wide and spans the full lenth of the house. The building faces north with the east and wet walls having no windows. We have no insullation in the walls or roof (as far as I can tell) and no crawl space betweem the ceiling and roof. Our electric bill (on the equilzer) plan has been $300 this winter. (We have not used our gas heater at all.) I am scared to death about the upcoming summer bills. I am searching for the most inexpensive way to keep my home cool this summer and at the same time save money. If I can’t do something about the miserble heat this year, I’m afraid I will have to move out of the desert! Can any one give me ideas of cheap ways to solve my problem???
April 29th, 2009 at 9:36 am
Bury a large insulated tank in the ground. Using a solar powered pump and a heat exchanger circulate the water/antifreeze through the system in the winter to cool it as much as possible. In the summer use the cool water to keep your home comfortable.