which is more cost efficient for central air?

Question

turning your a/c off at night or just keeping it on the whole time?

Answer 1

It depends on what turning it off means. If the AC is on, but not running then it isn't using any electricity. If you sleep with the windows closed and the AC off, and don't wake up covered in sweat - you are saving money without sacrificing comfort.

Part of the cooling effect of the AC is that it acts as a dehumidifier - removing moisture/humidity and making it feel cooler than the temperature. Sleeping with a window open in the summer can make your house more humid. When you turn the AC on the next day it has to work harder to remove the added humidity - using more energy.

Another twist - Energy efficient models have a circulation mode where even if the compressor is off, the fan still runs to circulate air - this doesn't use much electricity. If yours has this option, I would use it.

Mathematically speaking, the higher the difference of temperatures - inside to out, the greater the rate of heat transfer - so from a theoretical perspective it turning it off will save you money - but think of the comfort aspect as well.

Answer 2

It is a simple logic. Turning off a/c means no power bill. Keeping the a/c on (in operation) consumes electricity (hydro) and adds to the cost. Wear and tear will be additional cost, if the a/c is in operation. So, there is a price tag to the luxury. Although, turning off the a/c during night does not cause too much of irritation, since the ambient (outside) temperatures are generally lower than the day time. Hence, room temperatures do not go very high.

Answer 3

Central air doesn't require you to turn it off and on like you would a window unit. It is programmable. Set the temperature you like and leave it alone. The air will only come on if the temp. goes higher than you set and shuts off when it comes back to the set temp. In other words, it merely maintains your temp. Cooling down an entire home would take quite some time if you keep turning it on and off.

Answer 4

I don't agree that the AC should be held at a constant temperature at night. I would raise the setpoint at night for a couple of reasons.

First, the inside temperature will not rise as fast at night, because the outside temperature is lower than during the day. Yes it will increase inside, but the rate of heat transfer from hot to cold is partly dependent upon the temperature difference. As the inside temperature rises slowly, the rate of heat going into the house decreases. If you keep the inside temperature cool, then the amount of outside heat transferred into the house will be faster. If you wait until early morning to set the temperature to a lower temperature, you will have less heat to remove, because less heat has been transferred into the house.

Answer 5

Studies have been done on this. If you are home on a daily basis, it's best to keep your a/c on and the thermostat at a constant temp. If you turn it off, the a/c has a larger heat differential to overcome and actually ends up running longer and costing you more $$$$$.

Answer 6

Turn it off at night but leave the fan on, this will citculate the cool air from lower levels.

Answer 7

Leave your stat on the same temp year round! The hotter or colder the home is when that unit starts up, the higher you bill will be. The hotter the home, the more amps the unit will draw which is what makes your electrical bill so high. Leave it alone and you will save money!!
Also...using hot water, (shower, washer, dishes..etc.) eats up electrical bills more then ac unit!

Answer 8

leave it on