Is it more energy efficient to leave your AC on all the time or to use it only when you're actually home?

The best advice I can give is find a moderate temp you can live with, and if you wish the house to remain at that temp, leave it set at that even when not home,,,unless the period of time away is extensive.

Depending on where you live, how hot it gets during peak hours, how rapidly it cools after peak times of heat, it may be more efficient to leave it at 78 for example, all the time. In large measure it will also depend on how well the house is insulated.

Certainly when you're at home you can raise or lower the temp at will, for comfort, but to heat a non ac environment that has gone up to 90 or higher is inefficient, over the long term.

Rev. Steven

Generally, it is more energy efficient to only use your AC when you're home, especially if you just turn the AC on a normal tempurature, not crank it up to compensate in a short amount of time.

Granted, if you have an exceptionally large house, the time and energy it will take for your AC to cool down the house may certainly make it worth it to keep the AC on all the time in the long run.

Go to the local hardward or Home Depot and buy yourself a programmable thermostat. This will allow you to program both your furnace and your CAC to go on and off at specific times during the day. Rather then leaving on all the time, or turning on only when you're home, this route works the best and you can get a decent thermostat for about $50 CAD

If your house is well insulated turn AC down as you leave, say to 80. Then turn AC back to 74 as you leave work. You will save and be cool.

It makes more sense only when your at home and depending on how old it is probably safer.You can never be sure when a power surge or other electrical accident may occur!

Only when you are home.