Does it save money to turn the a/c off during the day and then back on when you get home?

my roommate and I are in disagreement, if we leave the a/c off or turn up the thermostat so that it doesn't come on as much during the day and then turn it on when we come home in the evening, does it save money? does the a/c have to work harder and use up more electricity cool the apartment down in the evening?|||The USEPA says both turning the temperature up and turning the AC completely off while you are not at home saves $$$.





The question is how much will either option save and will it be worth it.. for your comfort.





If I remember correctly simply turning the temperature up saves 2% per degree (F) that you turn it up. (so if you turn up the AC temperature from 74F to 78F you will save up to 10%.of your cooling cost.).





If you turn it up while you are away and at night and turn it down again while you are home you will save about 1/3 to 1/2 as much -- depending upon how long you turn it up, etc.





In extremely high humidity your comfort may matter most because at higher temperatures you may not be comfortable and it may take much longer to cool down.





Programable thermostats are inexpensive (I have seen them as low as $25) and can be used to do this automatically -- as someone else said -- it can be programmed to cool your apt down an hour or so before you get home so you will not feel too much of a difference and still save $$.





As to your last question -- does the AC work harder and use up more electricity when you cool down the Apt in the evening.. yes a bit. But the savings from turning it off when the temperature coasts upward AND from the lower temperature difference when you are holding your Apt at a higher temperature..should outweigh the extra electricity used when you cool it down again. (The temperature differential between inside and outside the Apt and the time this temperature differential is trying to be achieved is directly related to the cost of cooling.)|||if it is a window a/c then your wasting your money if it is your unit or central air then it is best not to turn it off and on - it is best to turn it down so it don't turn on but turnning the unit on and off uses more energy to turn on then it does to turn it down for 9 hours!


hope this helps!|||The best thing you can do is install a digital programmable thermostat. one that you can set it to be off when you're not home, and come on maybe an hour before you get home so its nice and cool.|||If you have high humidity outdoors, "catching up" can cost more than maintaining. I suggest turning the thermostat setting to run less in the day, but not turning it off.|||If you know how to read your electric meter, you can try it one way for a week and then the other, then see what uses less electricity.|||it will absolutely save you money if you turn it off when your not home...sure itll take a few minutes to cool the place off when you get home but the savings will be worth it. i cut my electricity bill by 40% by using a timer for my ac's