Ideal setting, in degrees Fahrenheit, for your air conditioner's thermostat.
We've received a number of inquiries from readers about the "best" temperature to set the thermostat during waking hours when they're at home, and apparently a number of utility companies specify 78°F. Obviously comfort is a subjective thing, one that also encompasses such other factors as relative humidity, airflow and its associated cooling provided by a fan, and even the clothes you're wearing.
For many people, an indoor temperature of 78°F during the summer is comfortable enough, especially if you also run a table, ceiling, or other fan when you're in a room. What's more, 78°F is a high enough setting that your air conditioning won't run as frequently, saving you money on your utility bills during cooling season. Each degree warmer you set the thermostat can save you about 2 percent. (What temperature do you set your thermostat to during cooling season? Take our informal poll* by clicking on "See the full article" below" or participate here.)
During a heat wave like the record-setting one that's recently blasted the East Coast, your air conditioning is likely going to run a good deal of the time even with the thermostat set to 78°F. While you do want to cut back on energy use during a heat wave, common sense suggests that you keep your house at a comfortable, safe level when the mercury rises.
Many of you keep the thermostat at a lower temperature than 78°F during the summer; indeed, at our daily news meeting this morning a few colleagues admitted to leaving the thermostat at 68°F.
Just be sure to be mindful of pets. And don't forget, 78°F is the summertime temperature. During heating season, set your thermostat to 68°F—or as low as you can take it.
—Steven H. Saltzman
Essential information: An accurate, easy-to-use programmable thermostat can help you cut your cooling bills by up to 20 percent. Our review of programmable thermostats includes ratings (available to subscribers) and illustrated installation instructions. Find out how to keep cool for less this summer.
*The poll is not scientific. It reflects the opinions of only those Web users who have chosen to participate. The results cannot be assumed to represent the opinions of Web users in general, nor the public as a whole. Consumers Union is not responsible for content, functionality, or the opinions expressed therein.
I took your challenge quite by accident. Raised it one degree - to 73 degrees F - and got no sleep that night. Horrible. We run our fan constantly to try to keep the two story somewhat even - the basement is cool and the upstairs sweltering.
I even installed a couple of supplemental blower fans for the bedroom.
I guess I will have to be even more 'green' in the winter time.
The step method described for finding a comfortable temperature leaves one important factor out of the equation: humidity. If you are stepping the temps up your AC is running less therefore dehumidifying less. 78F and dry is far more comfortable than 75F and damp.
You don't emphasize the importance of humidity, especially with respect to the outdoor humidity. Rather than a specific temperature, we find that setting the thermostat at a temperature just below the outdoor temperature is often enough to lower the humidity and add greatly to the indoor comfort. That may be 80+ degrees or 76 degrees, depending on the conditions. I know many people just want a "perfect" number and that's what you gave them. It's usually not that simple. I concede, when the outdoor temperature is 99 degrees a setting "just below" that may not be satisfactory. Likewise for those fortunate(?) enough to live where the weather is hot and dry a set temperature may work just great.
Thermostats, especially old mercury style ones, are notoriously unreliable when it comes to actual temperature. Home owners should invest in a modern digital thermostat and use it to monitor temps. They can raise temps during the day if no one is home and have the home at the right temp when they return (or lower it during winter months). So long as you allow it to raise (or lower in winter) for 8 hours or more it saves you $$$. These digital thermostats are relatively inexpensive, found at most hardware stores and large retailers, and simple enough to replace by the home owner. They can pay for themselves in a year or so.
It still feels too cold at 78. For me, 80 degrees is best. Get above that and it starts getting warm. At night, no change. The body slows down while sleeping and it does not need such a cool setting.
I admit it, I'm one of those A/C addicts. If money were no object, my space would be a chilly 68! Since I live in Baltimore which has one of the highest gas and electric rates, I've made myself comfy at 72. I have a programmable thermostat. I have two "short but" kittys so even when at work, the A/C stays on during hot weather which is 95% of our summers. As a matter of fact, it is not uncommon to use the A/C as early as May and as late as October! We get a lot of humid weather. When at work, I have my programmbale set in steps. I work at night so, during the late afternoon early evening hours before sunset, it's set at 75. Then from around 8 to midnight 78. From midnight to 2 AM back to 75 then after 2 AM my comfy 72. I also use floor fans. But, during the winter I can put up with the thermostat set between 55 and 60! I guess I have penguin blood.
Is anyone else disappointed with Consumer Reports? I find little knowledge available unless you are looking for a kitchen mixer. The site is hard to manuver around as well. Definately a 1 time subscription!
Time of day charging which has been increasingly implemented in the past couple of years is complicating matters. It is no longer possible to make sweeping statements like each degree F. increase in thermostat setting saves 2%. For example lets take 5 cents per KWHr from 9:00 P.M. to 7:00 A.M., 8 cents per KWHr 7:01 A.M to 10:00 A.M., 11.5 cents per KWHr 10:01 A.M. to 06:00 P.M., 8 cents per KWHr 06:01 P.M. to 09:00 P.M.. Holidays and Sat. Sun. 5 cents 24 hours.
My present strategy is to set the thermostat to 19 C. 09:00 P.M. raise it to 26 C 07:00 A.M. weekdays. On weekends/holidays I set it to 22 C. Obviously there is nothing scientific in my method and it is purely driven by by cost. The house is double glazed, mostly R17 with about 25% R8 in the walls R30 in ceilings. The highest temps so far this summer were 34 C with lows 22-24 C overnight. On those warmest days the thermostat clicks on (26C) around 4:00 P.M.
Yes, I too am very disappointed in my subscription. I wound up here while looking for a laptop fan… go figure.
At any rate, here in humid Ole San Antonio, I can take the entire (you may say what) winter at 0-60 degrees, and we rarely use the heat except when bathing.
Summers, now that's the hard part; with all the fans on I suffer from dry eye; with the AC at a comfy 72°(unless the humidity goes up) everyone else freezes. Now, I wear as little as possible in the house. We are talking a t-shirt and underpants! And I'm still prone to suffering with heat. So, we try with a ceiling fan on high in every room (2 in the larger rooms, and the AC at 74 and up until I can't take the humidity.
I want to paint my house a reflective silver, but that would just be cruel to the critters outside.
Cool post. Came across your blog on Google Blog Search. I’m going to add your RSS feed to my reader. Continue posting please!