Evaporative Coolers and Ceiling Fans 101 (and 202)
Question: Hi Randy. We enjoy your columns and have a question for you. We moved to Chino Valley earlier this year. Our house has an evaporative cooler and ceiling fans in the living room and bedrooms. We had never heard of an evaporative cooler, but our inspector told us they are as good as air conditioners and cheaper to operate. But, now that it's hot, we are not comfortable! We run the evaporative cooler and ceiling fans 24/7, but by late afternoon our home is too hot. The air coming out of the evaporative cooler vent does not seem cool at all. We really like the energy efficiency of an evaporative cooler, but not if we're not comfortable. Do you have any advice? (And what is "pump only"?) Cindy and Bob, Chino Valley.
Answer: Take my advice, I'm not using it. That's one of what my wife calls my "old man jokes." Another is "I could agree with you, but then we'd both be wrong." And my current favorite - "I'm confused. No, wait, maybe I'm not."
But I digress. Let's get back to advice, which I do have for Cindy and Bob. You need to understand how evaporative coolers (which I'll call "coolers") and ceiling fans (which I'll call "ceiling fans") work to get the best use and efficiency from them.
Coolers are relatively simple devices, are inexpensive to operate, and work very well in low humidity like we have here most of the time. Coolers have a water line that usually connects near a hose faucet or water heater. A cooler has a float valve that keeps the proper water level in the cooler. A small pump will circulate the water through small water lines and onto the pads. A blower will pull air through these pads and into the home. Coolers require a little more maintenance than air conditioners, primarily draining and covering them in winter and a thorough cleaning in spring. The good news is there are not many parts, and the pump and pads that need replacing occasionally are not expensive.
The water evaporating off the pads is what cools the air. If you get out of a swimming pool on a hot day, you are cool until you dry off. The water evaporating off your body cools you. This is the same principle. So coolers will not work nearly as well when it's humid, because less evaporating will occur to cool the air.
We have not had much rain recently, so coolers should be working well right now. If you cannot feel cool air when your cooler is on, you need to check the cooler itself. Make sure water is flowing onto the pads. I have found coolers not working because all the "tubes" were loose so the water was not going onto the pads. And of course it's possible the water pump has failed and needs replacing.
A cooler will be blowing a lot of air into the home, so you need to open a couple windows partially to allow the cooler to work properly. You mentioned a "single" supply vent for the cooler, which is common. If you have a single supply vent, opening windows in a room will "pull" cool air into that room.
The most common cooler control has five settings: low fan, high fan, low cool, high cool and pump only. The "pump only" setting turns on the water pump so you can saturate the pads before turning on the blower. Otherwise you would get hot air for a while when you first turned the cooler on. The "cool" settings turn on the pump and blower, and the "fan" settings turn on only the blower. This is useful if it's humid out and you don't need the pump but want some "fresh" air in the home.
Now for Ceiling Fans 101. We are back to "evaporation." With a few exceptions, ceiling fans only work if you are sitting below them. I cannot count the times I've gone into homes where nobody is home and every ceiling fan is on. This actually heats the home (heat from the electric motor), uses electricity and accomplishes nothing (unless the seller is trying for a dramatic "effect" for purchasers, but this is totally wasted on home inspectors).
People don't seem to believe me about this. But I know that we all know that everything on the internet is true. I copied the following from Wikipedia:
"In summer, the fan's direction of rotation should be set so that air is blown downward. The blades should lead with the upturned side as they spin. The breeze created by a ceiling fan speeds the evaporation of perspiration on human skin, which makes the body's natural cooling mechanism much more efficient. Since the fan works directly on the body, rather than by changing the temperature of the air, during the summer it is a waste of electricity to leave a ceiling fan on when no one is in a room."
So running your fans "24/7" not only wastes electricity but actually puts a little heat into the home. I have demonstrated this to people by using my infrared ("laser dot") thermometer to show how hot a ceiling fan motor can get during normal operation.
By the way, Cindy and Bob are not their real names. I emailed my advice to them, and they replied that they had turned on the water to the cooler on to fill it up, but did not realize it had to stay so they had turned the water back off. The cooler is working much better now with the water on. They felt silly and asked me not to use their real names. I feel this is an honest mistake since people from humid areas have no idea how a "swamp cooler" works. But I changed their names.