Turning A/C up during the day

[Nick1994]

I've looked online but haven't really come up with a good answer.

I'm wondering if it's more energy efficient to turn the A/C up a degree or two during the day saves a measurable amount of energy. I'm thinking no since the electric company charges more during the evening when I get home from work when I would turn it back down. Also the A/C has to run to cool the house down. Today it hit 106 degrees and the A/C was set to 74 and I was warm so I turned it down to 73 and it ran for over an hour to cool the house down, it's never seemed to do that before but it was also 4:00 and it was really hot.

I'm not interested in keeping the house warmer while home, the energy savings aren't important enough to be uncomfortable, was just curious if I should turn it up a degree or two while walking out the door for work in the morning or just leave it set to 73 or 74.

Thanks.

 

[bdcardinal]

Do you have a programmable thermostat? They make ones that will automatically raise the temp at a certain time.

I think a couple degrees over a long time span will be worth the savings on your power bill. Are there any pets at home that would have to adjust to the temp change?

 

[Nick1994]

Originally Posted By: bdcardinal
Do you have a programmable thermostat? They make ones that will automatically raise the temp at a certain time.

I think a couple degrees over a long time span will be worth the savings on your power bill. Are there any pets at home that would have to adjust to the temp change?
It isn't programmable but it is digital, and is 3 1/2 years old as is the central A/C unit. I wouldn't mind just pushing a button on the way out the door. I do have dogs but a couple degrees isn't going to make a difference for them.

 

[bdcardinal]

I say try it and keep track on your power bill.

 

[AdRock]

You can get a programmable thermostat from Home depot pretty cheap. I put one in a few years ago. I have it so that at 9am it goes to 78 and then at 3pm it goes back to 73 until the next morning. The electric bill did go down some but I can't remember how much. If your house is well insulated the temp won't change that much over the course of the day. On a 100f day, the temp inside the house only drops to about 76-77 by the time the thermostat switches back to 73.

 

[901Memphis]

59F before i go to bed, and back to 65F when i'm awake.

 

[CT8]

My rates are higher from noon to 7 o'clock where I live.

 

[Leo99]

Originally Posted By: 901Memphis
59F before i go to bed, and back to 65F when i'm awake.


Glad I'm not paying your electric bill. I keep my AC at 76 when I'm home and 80 when I'm at work.

 

[OneEyeJack]

My house has a "smart" meter. They charge different rates at different times.

I open my house at night and it cools down. In the morning I close the house up and it will stay cool until about 2 in the afternoon on the hottest days. The A/C might be used from about 2:30 until 6. It then starts to cool down with the ocean breeze and the cycle starts over.

I've been careful to place trees in the way of the afternoon sun. I get the volunteers that start up all over the back couple of acres and transplant them around the house. It's really works over the past 10 years. These "wild" trees grow fast and don't require any special attention. I have no idea what they are but that's okay.

At 12 noon it can be 100F outside and inside it's 65 with the house closed up and no A/C. All I have to do is keep the cycle going.

 

[901Memphis]

Originally Posted By: Leo99
Originally Posted By: 901Memphis
59F before i go to bed, and back to 65F when i'm awake.


Glad I'm not paying your electric bill. I keep my AC at 76 when I'm home and 80 when I'm at work.


It's not too bad, last month i used 715 KWH and the bill was only $86.

The worst month i've had was last year in June i used 1381 KWH, but the bill total isn't showing up from that long ago.

 

[Merkava_4]

Originally Posted By: 901Memphis
59F before i go to bed, and back to 65F when i'm awake.


You're talkin' about the heater right?

 

[slowdime]

Not sure what the night time temps are like in Phoenix, but it may be worth opening up all the windows when the outside temp is lower that what your t-stat is set to. During the day keep all your blinds closed, some blackout curtains should help keep the cool in.

 

[Brad_C]

Originally Posted By: Nick1994

I'm wondering if it's more energy efficient to turn the A/C up a degree or two during the day saves a measurable amount of energy.


Absolutely. Heat infiltration is directly related to differential temperature. The colder it is inside the more heat (in energy terms) that passes through the house envelope and the more energy your A/C is required to remove. The smaller the differential, the smaller the required energy to maintain it. By the time you've got home from work it has cooled down a couple of degrees outside and you can drop the thermostat a couple of degrees. It will take some time to cool down the house and contents that couple of degrees, but with the much smaller heat input from outside its a net win.

 

[Shannow]

Originally Posted By: 901Memphis
It's not too bad, last month i used 715 KWH and the bill was only $86.

The worst month i've had was last year in June i used 1381 KWH, but the bill total isn't showing up from that long ago.


Family of 4, we used 1379 for the last quarter...$355.91 WITH my staff discount.

 

[supton]

I think it depends upon how fast the temp in your house can change. Thermal mass and all. In my house, we have to leave the window units cranked during the day as a) they can't keep up and b) they have a nasty tendency to shut off during the night, when we need them the most (nighttime temp might drop down to 60, even less, but with brutal humidity, and an inside temp still in the high 70's).

I would try and see how your meter responds. Do a couple of weeks.

 

[Tzu]

Sounds logical. In an opposite situation, I have our furnace set to 67 degrees when I'm at work in the winter and it goes to 70 degrees 30 minutes before I get home. It probably depends on how quickly your A/C can recover. Living in what is known to be one of the hottest parts of the country, I'm sure it is big enough to recover quickly. It will no doubt save money. Try it for a month and look at your electric bill.

Yeah, the cold sucks here sometimes, but I can't imagine doing anything outside when it's in the 100's on a regular basis either. Wow.

 

[HerrStig]

The system will be more efficient when the air moving over the condenser is cooler.

 

[Dave Hess]

Yikes. 106 degrees and its not the hottest part of the year yet.

 

[Cutehumor]

Originally Posted By: 901Memphis
59F before i go to bed, and back to 65F when i'm awake.


My sister sets her AC at 65 degrees too because of her husband. in Memphis, she gets hit with near 300 dollar electric bills from MLG&W last summer!

 

[yeti]

o.p.-- since you live in a desert, residential climate control will likely differ from those in a different climate.try asking friends/neighbors in your area what they do in their homes.good luck.