When to crank your AC.

[Color Me Badd Fan]

This isn't exactly a home improvement thread, more of an energy efficiency thread.

I've been wondering which is the more efficient way to operate your AC:

Option 1: Keep the thermostat at around 76 when you wake up. The AC turns on about twice an hour and runs for a few minutes until about 3:00 when the AC has to turn on more frequently/run longer to keep the temperature steady. Assume a temperature at 7:00 AM in the low 70s and the temperature peaking around the mid to high 90s by the late afternoon/early evening.

Option 2: Crank the AC up to about 70 when I wake up. Conceivably, my AC wouldn't have to kick in until the late afternoon/early evening--although I'm not entirely sure how fast my house will heat up, it could be around 3 or even 2 on really hot days. My idea is that my AC in the early morning wouldn't have to work as hard to get the temp down to 70 because that's the temperature outside as opposed to having run steadily at 76 when the temperature has already reached the 80s by around 10 and the low 90s by around noon.

[Babs]

I'm a little confused. You're asking whether it costs less to keep your house at 70 or 76 during the day?

[Color Me Badd Fan]

I'm a little confused. You're asking whether it costs less to keep your house at 70 or 76 during the day?

No, crank it up to 70 in the morning when it' s about 70 outside, and then set the thermostat back to 76 when the house is cooled down to 70. The idea is the AC won't turn back on until around 3 or 4:00 because the house is so cool early in the morning.

[Portland Ute]

I'm guessing, without any sort of expertise but based on what little science I know, that the cost difference would be negligible.

If it's 90 degrees outside, you are going to have to use a certain amount of energy to keep the inside of your house at 76 degrees during the hottest part of the day. Getting a "head start" just spreads out the energy expenditure during the entire day.

[Donuthole]

Good luck getting your wife to let you crank it to 70. That's grounds for divorce in my house.

[Babs]

In terms of cost, everything I've ever seen has said to keep your thermostat set as high as possible for as long as possible. But setting that aside, another consideration is that by keeping the house at 70 until 3:00, 76 is suddenly going to seem awfully uncomfortable at 4:30.

[wuapinmon]

Good luck getting your wife to let you crank it to 70. That's grounds for divorce in my house.

One of my favorite things about my wife is that she likes it cold inside. I guess growing up in the desert makes her shun the heat.

[Uncle Ted]

This isn't exactly a home improvement thread, more of an energy efficiency thread.

I've been wondering which is the more efficient way to operate your AC:

Option 1: Keep the thermostat at around 76 when you wake up. The AC turns on about twice an hour and runs for a few minutes until about 3:00 when the AC has to turn on more frequently/run longer to keep the temperature steady. Assume a temperature at 7:00 AM in the low 70s and the temperature peaking around the mid to high 90s by the late afternoon/early evening.

Option 2: Crank the AC up to about 70 when I wake up. Conceivably, my AC wouldn't have to kick in until the late afternoon/early evening--although I'm not entirely sure how fast my house will heat up, it could be around 3 or even 2 on really hot days. My idea is that my AC in the early morning wouldn't have to work as hard to get the temp down to 70 because that's the temperature outside as opposed to having run steadily at 76 when the temperature has already reached the 80s by around 10 and the low 90s by around noon.

Option 3: Get an A/C with thermo storage:

The idea behind these thermal storage systems is to run air conditioners at full tilt during the night when the demand--and in many cases, the price--for electricity is lowest.

Standard air conditioners circulate a refrigerant through coils which creates cold air through a heat-exchange process. By cooling the refrigerant with cold water during the hot times of the day, air conditioners do not need to work as hard to cool the air and remove humidity.

The savings from this "peak-shaving" setup can be significant.

[il Padrino Ute]

It's difficult to figure out the innuendo in the thread title with all this talk about cooling the house. Unless, of course, cooling the house is another innuendo.

[Color Me Badd Fan]

In terms of cost, everything I've ever seen has said to keep your thermostat set as high as possible for as long as possible. But setting that aside, another consideration is that by keeping the house at 70 until 3:00, 76 is suddenly going to seem awfully uncomfortable at 4:30.

Once again, the thermostat is only set at 70 long enough to get the temperature inside to 70 and then the thermostat is immediately set back to 76. I figure at around 7:00 AM, the AC would run full tilt for about 30 minutes. For portion of that, the AC would run in the second phase which takes more energy.

The advantage is that it's easier for the AC to cool the house down to 70 when it's the same temperature outside than it is to keep it at 76 when it's 90 outside. Eventually, the AC has to kick back on, but that's probably not happening until around 3:30. The drawback is the unit would have to run on the second phase for a while when you're getting the house down to 70.

Additionally, I wonder if letting the AC just run continuously for a half hour as opposed to cycling in and out for a few minutes at a time puts less wear and tear on the condenser.

[jay santos]

A guy i worked with told me he had two heavy duty fans he would sit in large windows on each side of the house and blow air in one side and air out the other side. He'd run these all night and the house would be so cooled off in the morning, he'd only need to run a little AC towards the end of the day. I always thought i'd like to test this but never have.

[Babs]

Once again, the thermostat is only set at 70 long enough to get the temperature inside to 70 and then the thermostat is immediately set back to 76. I figure at around 7:00 AM, the AC would run full tilt for about 30 minutes. For portion of that, the AC would run in the second phase which takes more energy.

The advantage is that it's easier for the AC to cool the house down to 70 when it's the same temperature outside than it is to keep it at 76 when it's 90 outside. Eventually, the AC has to kick back on, but that's probably not happening until around 3:30. The drawback is the unit would have to run on the second phase for a while when you're getting the house down to 70.

Additionally, I wonder if letting the AC just run continuously for a half hour as opposed to cycling in and out for a few minutes at a time puts less wear and tear on the condenser.

okay. I gotcha now. I don't know. I think you should try it for a week and see how it goes. I wouldn't think lowering it to 70 in the morning would help much, but then I'm writing from a place where it's super humid doesn't drop below 78 at night.

[Color Me Badd Fan]

A guy i worked with told me he had two heavy duty fans he would sit in large windows on each side of the house and blow air in one side and air out the other side. He'd run these all night and the house would be so cooled off in the morning, he'd only need to run a little AC towards the end of the day. I always thought i'd like to test this but never have.

This definitely works. The key is getting them on each end the house so you get an air current going through the house. The problem with my house is that I have a ton of windows on the east side of my house and only one window on the west side that opens up and that one window faces our walkway and isn't directly across the house from my east facing windows, it also is perpendicular to the door of the room. I have a big window that faces north and I have had better luck with opening that up and getting a breeze with the east windows.

[cougjunkie]

I am still waiting for the new compressor for my AC. At 9pm tonight it was 92 degrees inside my house.

[Coach McGuirk]

I am still waiting for the new compressor for my AC. At 9pm tonight it was 92 degrees inside my house.

I'm at 89.