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.