It didn’t start out as a challenge to myself. Ultimately, that’s how it evolved but not why it succeeded. I’m talking about NOT running our central air conditioning units the entire summer. In fact, I didn’t even take the winter covers off (pix below). This despite the fifth hottest July on record in Salt Lake this year, a hotter-than-average June, and 2007’s being the hottest summer here EVER.
The reason? Were were out of town for a couple of weeks during that time. But the major reasons were our solar PV electrical system and our evaporative or, as popularly known in the west, “swamp” cooler (pix left). Its principle is quite simple: a ferris wheel in a box on your roof blows naturally cooling mist using water from your home into your house keeping the temperature down and acting as a ceiling fan/giant spray bottle.
Ol’ Swampy kept our house 15-20 degrees cooler than outside even on the hottest days. Luckily, the humidity during this time was low (10-25%) which is how the swamp cooler works its magic. Above 25%, it doesn’t work very well which is why you don’t see them much outside of semi-arid
climates like Utah’s. What’s more, swamp coolers use about 75% less electricity than central air conditioners and an “advanced ducted” system (we don’t have one of those) can save up to $10,000 in operating costs over the 15-year life of the system.
I can’t tell you what our total savings over last summer are yet. I have some more number-crunching to do. But 2007 was hotter than this one and we mostly ran the AC. I can tell you that combined with our solar panels, our electric bill for mid-June-mid-July this year was $28.20. Last year during that period, we spent $122.40. From mid-May-mid-June 2007 (a scorcher), we experimented with our then-new solar system, ran totally off-grid and paid $8.20 (the hot tub’s on 220v). That same period this year, we were grid-tied and net-metered and paid $34.07. July-August 2007 was $122.40. We haven’t gotten the bill for that period this year yet.
Swamp coolers use water but not nearly as much as you’d think. And with routine maintenance, not enough to make much of a difference in your water bill. From June 8-July 11, 2007, the hottest month on record in Salt Lake, we spent $68.03 on water. This year during the same period (slightly cooler), we spent $62.19. The water bill from July 12-August 9, 2007 jumped to $151.75. We haven’t gotten our bill yet for that period this year but I’m expecting it to be similar or less. I’ll let you know.
At a glance, the combination of the solar panels and the swamp cooler is a massive economic and environmental savings. There are some critics of swamp coolers who point out that swamp coolers suck in pollutants from the outside air that can cause you problems. But central, car and industrial air conditioners, especially the older ones, give off HCFC (hydrochloroflurocarbons) that deplete the ozone layer, aggravating the problem even more. As for sacrificing comfort, if it’s 100 degrees outside and 80 degrees inside and you can’t feel and live with the difference, you need your blood pressure, not your air conditioning checked.
The question is: which do you want? More ozone in your home or creating more ozone that will eventually get into your home anyway? Not an easy choice. But because airborne ozone and pollutants vary in intensity from day to day, and an air conditioning unit gives off HCFCs all the time, it makes more sense to run the swamp cooler from a personal, and environmental and a neighborly standpoint.
Bottom line: if you live in the western U.S. in a semi-arid or desert climate, there’s no reason not to have an evaporative cooler. They’re cheaper to buy, install, operate, are much lower maintenance, use 25% the electricity of an air conditioner, don’t use much water, have far less impact on the environment at large and maybe equal the health impact inside your house as AC. When Nature gives you heat and drought- don’t whine. Get a swamp cooler, some solar panels and laugh all the way to the bank.