Funny about Money

The only thing necessary for the triumph of evil is for good men to do nothing. ―Edmund Burke

Programmable Thermostats: Aren’t they supposed to save on power?

So the electric bill arrived in the mail, bearing news of a stiff gouge out of my checking account. Comparing this month’s bill, the first of the air-conditioning season, with what I paid for the same period last month, what should I find but that this year’s bill is $50 more than last year’s! And this year we had a fairly cool spring. Andddd….this month was the first time I used the new programmable thermostat.

The power company, Salt River Project, raised its rates 3.9 percent in January. That should have increased my bill by about $13, not by fifty bucks. And the newsletter SRP stuffs into its billing envelopes announced that SRP plans to raise rates again!

Well, the only thing that’s changed has been the advent of the programmable thermostat. During the winter, I didn’t use it at all—the experiment to rely on space heaters to keep warm worked, and I didn’t turn the central heat on more than two or three times, for an hour or two at a time. A couple of months ago, M’hijito came over and figured out how to set the thing so it would run at 79 degrees during the day (I wanted 80 degrees, but he thought that would be too hot) and then drop to 76 degrees between 10:00 p.m. and 5:00 a.m., so I would at least have a shot at sleeping all night.

About 76 degrees is where I used to set it at night when I had the old-fashioned round analog thermostat. I did keep it at 80 during the day, but it doesn’t seem like one degree should account for a $37 spike.

There could be some user error here: the instructions are so cryptic, I can’t understand them at all. When I try to figure out how to set it, it’s just like reading Chinese—utterly incomprehensible. My son, who uses his own programmable thermostat with ease and success, took quite some time to parse out the way to work mine. And he’s pretty clever with electronic gadgetry. Entertainingly, the AC people said this is their easiest-to-use model. 

The only thing I can figure is that programmable thermostats are not what they’re cracked up to be. Either the old analog model was inaccurate and the temperature in my house was higher than 80 degrees, orrrrrr….. oh yes: the story that leaving the AC off until you can’t stand it overworks your system and jacks up your bill JUST…AIN’T…SO.

Afraid so: that’s actually what I used to do. Because in my dotage I no longer can sleep in a warm room, I would ratchet the thermostat down to 76 (or even…hang onto your hat: 72!) at night. Then I would turn it off when I got up, around 5:00 or 6:00 a.m. I would leave it off until I couldn’t breathe any more, which on a normal 105- to 110-degree day occurs around noon. By then it would be bloody hot indoors. At that point, I’d turn on the unit and set the thermostat to 80 degrees. 

Air-conditioning techs will tell you no, no, no, no: you must keep the house at an even temperature at all times. If you don’t, we’re told, the structure will become “heat-saturated” and instead of cycling on and off, the unit will run nonstop. This, they say, will result in higher, not lower, air-conditioning bills. 

Huh. That appears to be the exact opposite of empirical experience. Another emperor has no clothes, eh? 

Images from Wikipedia Commons:
Analogue thermostat by Flicker user
Programmable thermostat by

Author: funny

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  1. I have the same issue when at my sister’s in Vegas. I usually turn the a/c off when she leaves for work @ 6 pm. I keep a small fan in the bedroom at night. Place small thermometers in each room. See what your “real” comfort level is. Adjust your timing. Maybe 85 until noon? I find fans help me more than the a/c. I move a chair under the ceiling fan for reading.

  2. I know in our neck of the woods, the importance of setting our thermostat and only touching it rarely–is all about wringing the humidity out of the air. If we turn it off or down, the humidity builds back up.

    That shouldn’t be a problem in your area though.

  3. @ Brenda: I keep the house in the low 80s during the day. And I live for fans! 😉

    When you reach a certain age, though, you may find you can’t sleep at night unless the bedroom is fairly cool. That was why I had the idea of putting a room air conditioner in the wall back there–naturally, by evening my bedroom is the hottest room in the house. Several people, however, advised against this on the theory that it would damage the salability and possibly the selling price of the house: it’s a tip-off that something’s wrong with the HVAC system.

    @ Terri: Humidity isn’t a problem until mid-July and August. We have a summer rainy season, and then it can get pretty damp around here. Most people who have swamp coolers also have regular air-conditioning. Swamp coolers are very effective in April, May, and June — and very cheap. But in July and August, they not only don’t cool effectively, the extra humidity pumped into the dwelling just makes you miserable.

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