is it better to leave the AC on all day, or turn it on at night to cool down a lot

[kcthomas]

Its gettin hot in AZ, im gone all day. Does it take more energy to cool down the house 10+ degrees at night, or to leave the ac on all day?

 

[Ronstang]

If you are going to be gone all day then cooling down the house when you return is more efficient. If you have a digital thermostat just program it to keep the temperature rather high in the middle of the day and cool it down about 20 minutes before you return.

 

[Linflas]

I have mine set to 78 during the day when we are out, it switches over to 72 about 30 minutes before we come home.

 

[pontifex]

i have my ac off when i go to work and set it to turn on like 2 hours before i get home.
haven't had to use it this year but i used it all the time last summer.

 

[b0mbrman]

Check the archives...I believe there was a post on this and someone explained all the science behind it.

Has something to do with your furniture, floors, walls and such retaining some of the A/C (or heat in the winter, for that matter) if I recall correctly