Don't Worry About Swamp Cooler Water Consumption

People sometimes worry about the water consumption of an evaporative cooler.   I found this information in an NREL report:

"on a Btu-of-cooling-per-kWh-of-electricity basis, the best evaporative cooling systems are on the order of five times more efficient than SEER 13 central air conditioning (CAC) systems and demand is less by a factor of four or more. Further, additional water use at the site (home) amounts to only about 3 percent of the water use of an average residential customer."

So don't let water costs drive you away from swamp coolers in Denver.

However, if you are building a new, smallish, superinsulated low energy home, you are better off going with a mini-PTHP for heating and cooling.  A swamp cooler requires more maintenance and seasonal mode changeover, which is awkward due to seasonal overlaps like "Indian Summer".

Praise for Swamp Coolers (in Denver)

We've got a bit of a heat wave going in Denver right now, so I felt compelled to brag a little about my $400 air conditioning system.  If you look at this photo closely, you can see that the temperature of the top floor of my house was 59F this morning, after running the AC all night.  Doesn't this seem wasteful?  After all, the EPA recommends a 76F setting for your air conditioner.

Well, no, it isn't.  My AC is actually an evaporative cooler which is really just a ventilation fan that passes the ventilation air (3500cfm in this case) through a water-soaked pad.  It costs me only $0.80/day (7 kwh/day) to get my house this cold during 90F weather.  What many folks don't understand, however, is that when it's hot (over 86F), you shouldn't run the thing during the daytime.  It should be off from about 9am to about 8pm, with the windows in the house shut tight.  Apparently the swamp cooler manufacturers don't understand this either, or they'd be selling controls with timers at Home Depot.

And I'm not feeling guilty about contributing to global warming, because I'm actually cooling down my neighborhood when the cooler runs.