Screw that. I set my AC where I'm comfortable. Don't care if my electric bill is $20 or $30 more. Well worth it.
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Air Conditioning- The Best Formula for Temp Management
- Thread starter Huntn
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Good point. So on a 90° day maintaining 71° is a 19° difference, versus 75° which would be a 15° difference. That makes sense. I think you've answered my question.
Let's say it's 100° outside and you've set the temperature to 85° during the day, but you want it 75° when you get home. I have to assume the amount the AC will have to run to drop the house temp by 10° , although it will run a long time, will be less than holding 75° all day.
How much are you AC bills in the Summer, where do you live? I know people who have $400 electric bills in the Summer. Mine runs much less, because for one thing when we moved into our current house, I put in an efficient Trane AC and had 2' of cellulose blown into the attic. Going from 4-6" to 2' made a HUGE difference, in the heat of Texas (Houston area), 95-100° for last month or so, about $160-200. We keep the temp 75° in the day and 73° at night.
Based on some somewhat limited research I've done on this, for the most part it seems cooling down to a temperature you want closer to the time you want it is somewhat better than maintaining that temperature the whole time. Of course it depends on whether you are around or not, and then also how hot it is plays a role as it would take longer to cool down on hotter days (not letting it get too hot when you are not around can help with that).
I do too, when I'm home. But there is no reason for me to keep the house 70° when nobody is in my house. So from 8am to 4pm I turn the AC up to 80°. By the time we get home at 4pm the AC has kicked back on and the house is back to 70° and stays that way until 8am the next day. My thermostat is smart enough to know approximately how long before 4pm it needs to kick back on to get down to 70° by 4pm. So on some days when it is only 75° outside it might only have to run for 10-15 minutes before 4pm. Other days when it is 90°+ outside it might have to run for an hour. I don't really care though since it is 70° when I walk back in the door.
I would consider setting it higher than 80° during the day since my home is insulated/sealed up pretty well, and my AC is pretty efficient, but I have pets so I don't want it getting too much warmer than 80°.
Correct, running it once to drop the temp 10° right before you get home will take less energy than running it numerous times throughout the day trying to keep it at 80° and then only having to drop 5° right before you get home.
The problem is the size of your home and efficiency of your AC and insulation and how long it takes to drop that 10°. If your system has to run for 4 hours to drop the house 10°, then it might not make sense to let your house get up to 85°. If it only takes 1 hour to drop 10° then it will likely be worth it.
Agreed.
We feel the cold.
Actually, I wondered when someone would raise this: I like heat, - and really feel and detest the cold - and I have noticed that men seem to prefer cooler rooms. In modern hotels, I have had to ask the front desk (they always have these incredibly complicated indecipherable controls) for instructions on how to increase the room temp, and these rooms seem to me to be uncomfortably cool.
Likewise, with duvets; in winter, two duvets - and, an electric blanket - are my preference.
Besides, 64F is on the cool side of cold - and that is something that means wearing warm pullovers inside.
Where it causes the most problems is in companies. The men will complain how it's too warm while the women complain it's too cold. I personally think it should be on the cool side since it's easier to add clothing.
Hahaha, same here, see "unplugging electronics" thread
Me too. I also live in an apartment so changing the t-stat out is an issue. I set it to 75 and it runs whenever it needs to. I'm on budget for my electric bill and it's usually under $70 a month when averaged between summer and winter. Actually, I haven't paid a bill in 3 months as catch up from over-paying all winter.
Yes, I live alone.
Oh, god, yes, in companies.
Well, I'm one of those who think it should be on the warm side.
Actually, I have an enormous tolerance for heat, I realise.
While I usually have an open window in my bedroom, - the room itself is heated, and the bed, well, the bed, is, um, tropical. Even for me, a duvet can be occasionally too warm in summer. And, even for me, there have been nights when I realised that two were excessive.
However, to be honest, I loathe air conditioning; I only use it when there is no other alternative.
My bedroom AC stays on on during the summer and I keep my bedroom window cracked open during the winter. Needless to say I'm single
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My bedroom AC stays on on during the summer and I keep my bedroom window cracked open during the winter. Needless to say I'm single
Well, my bedroom window is open, winter and summer.
But the heat is on, as is the electric blanket, and - just to make absolutely certain I stay nice and cosy, in winter, I usually have two (yes, two) duvets (natural eiderdown) on my bed.
In those circumstances, it should probably come as no real surprise to learn that I, too, am single.
I find nothing is better for sleep then a cold room and lots of blankets. I'm not a happy sleeper during the summer
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64 F! I would have to get the sleeping bag out!
Residential air conditioners are, for the most part, constant - meaning they're either on or off. They run at 100% or they don't run. So they don't really run any more "efficiently" on one day than they do any other (based on temperature), they only run for longer or shorter times.
Naturally, if you let your house temperature drift up to 85 while you're not home and then cool it off to 72, that cooling off period would use more energy (total, not per unit time, which is power) than if you kept the indoor temp at 80 then cooled it off to 72; however, you would be using more energy to keep the house at 80 during the day than you would use to keep it at 85.
I use programmable thermostats in my house. The temperature drifts up to 85 during the day, and shortly before I return at 6 pm the units cycle on to bring the indoor temp down to 76, which is more than comfortable for us most of the time.
Higher tech air conditioning equipment (such as those used in data centers and hospitals and such) actually DO operate more efficiently with a higher return air temperature, but that's not really dependent on the outdoor air temperature, it's a function of heat gain in the conditioned space. But that doesn't really apply to residential splits.
Naturally, if you let your house temperature drift up to 85 while you're not home and then cool it off to 72, that cooling off period would use more energy (total, not per unit time, which is power) than if you kept the indoor temp at 80 then cooled it off to 72; however, you would be using more energy to keep the house at 80 during the day than you would use to keep it at 85.
I use programmable thermostats in my house. The temperature drifts up to 85 during the day, and shortly before I return at 6 pm the units cycle on to bring the indoor temp down to 76, which is more than comfortable for us most of the time.
Higher tech air conditioning equipment (such as those used in data centers and hospitals and such) actually DO operate more efficiently with a higher return air temperature, but that's not really dependent on the outdoor air temperature, it's a function of heat gain in the conditioned space. But that doesn't really apply to residential splits.
You are referring to the old one-stage A/C units. There are plenty of 2-stage A/C units available for residential use. Hail, I just replaced a 30 year old 1-stage 4 ton unit with a 2-stage 5 ton unit last year. It's great for hot and humid climates like Houston. Most of the time it runs at 2/3 capacity, but ramps it up to 100% when it's hot, hot, hot.
My minisplit system costs less to operate 24/7 than my window units did intermittently. Remarkable device.
I don’t have AC so it’s about opening and closing windows on the appropriate side of the house, meanwhile also drawing and putting up window shades. I don’t really like temps above 72ºF and don’t mind it being a whole lot colder than that, so in the mountains this usually works out okay.
In summer here, the mean night temp outside is 55ºF. The 24-hour mean July this year was 72, last year 68. Our daytime temps can run into high 80s but a stretch of 90s, no.
Once in awhile I forget to draw the west side shades upstairs in the morning, so I end up having to use a box fan on exhaust after nightfall up there for a couple hours before I head up to sleep. Barring that I usually need blankets at night since I leave the windows open unless I think it will get down into the 40s.
I like to have the whole place down to around 50-55 by 6am when I start shutting the place up against the heat. It usually doesn’t get above 70-75 inside during the day even with the windows open on the “dark” side of the house, as long as I keep the shades drawn on the sunny side. I’ll even open the sunny side windows if there’s a breeze.
Only thing wrong with this setup is when it rains sideways, must close up the weather-facing windows. And then if the breeze drops but I know the storm’s circling for another pass, it’s stupid to open windows prematurely. At that point I’m likely to go out on the covered deck for some air in between passes of the storm.
My elec bill runs $30-$40 a month max all year round since I don’t have a lot of stuff takes high juice. We joke about low bills around here as being partly due to power outages but it's mostly due to not using clothes dryers, AC or electric heaters. Wool sweaters are pricey but they last forever.
In summer here, the mean night temp outside is 55ºF. The 24-hour mean July this year was 72, last year 68. Our daytime temps can run into high 80s but a stretch of 90s, no.
Once in awhile I forget to draw the west side shades upstairs in the morning, so I end up having to use a box fan on exhaust after nightfall up there for a couple hours before I head up to sleep. Barring that I usually need blankets at night since I leave the windows open unless I think it will get down into the 40s.
I like to have the whole place down to around 50-55 by 6am when I start shutting the place up against the heat. It usually doesn’t get above 70-75 inside during the day even with the windows open on the “dark” side of the house, as long as I keep the shades drawn on the sunny side. I’ll even open the sunny side windows if there’s a breeze.
Only thing wrong with this setup is when it rains sideways, must close up the weather-facing windows. And then if the breeze drops but I know the storm’s circling for another pass, it’s stupid to open windows prematurely. At that point I’m likely to go out on the covered deck for some air in between passes of the storm.
My elec bill runs $30-$40 a month max all year round since I don’t have a lot of stuff takes high juice. We joke about low bills around here as being partly due to power outages but it's mostly due to not using clothes dryers, AC or electric heaters. Wool sweaters are pricey but they last forever.