If you set your central AC on a temp...shouldn't it keep your house cooled to the set temp?

Question

I had the temp set at 78, it's 90 outside and my thermostat reads 82??????

Answer 1

On digital thermostats, yes. Analog... No.
Are you uncomfortable? If so you might have an AC problem. If your problem is only the discrepancy between the set temp and the room temp, know that the thermometers in many thermostats are not very accurate. On NON digital thermostats the room temp indicator isn't even connected to the system and is there only for you to look at. Use an accurate thermometer to see which indicator is accurate and adjust your setting respectively.

Answer 2

Not necessarily. If the thermostat is one of the old mercury filled ones and not a digital, it may not even be showing an accurate temperature on it. Most of their accuracy comes from being exactly level, the least bit off and they won't give an accurate reading, or more exactly call for the system to shut off when the correct temperature is reached.

Even though it is only 90 outside, if you have a lot of windows in your house facing East and West, you get a lot of heat build up in your house from the radiant heat of the sun, so the system may be doing all it can. Does it cool to 78 after the sun goes down? This may be your problem.

Answer 3

Not if the unit isn't big enough for the square footage of the house. Or you may need freon. Check and make sure your ducts aren't covered by furniture so the air in the house is circulating freely. There are a lot of reasons why your AC may not be keeping up. Call the air conditoning repairman and get the unit checked if it's bothering you. Or just turn the thermostat down a bit until the heat wave passes.

Answer 4

Leaving it off until you need it saves money, but isn't as comfortable because it takes a while for the temperature in the house to reach the set temperature. Get a programmable thermostat if you can hook one up to your air conditioner. Set it to turn on (about 78-80 degrees) an hour or so before you return home, if on a regular schedule. The house will be nice and cool when you walk in.

Answer 5

What and how many windows do you have without proper covering to keep your temps down? Yes, the central air will try to keep your temp but if you are defeating it with improperly treated windows, you are spending more money trying to get at that temp. Low E windows also help with your efficiency. But the sun streaming in is a powerful element so maybe you need to look at more efficient windows or window treatments.

Answer 6

there is a problem with your air conditioner. or maybe the filter thing needs replacing.... its hot why would u even up ur ac on 78 ? try putting it on 70 or 72