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Anyone here? Question about air conditioning.
I've got an air conditioner and it's a real energy hog. The electric bill goes way up in the summer.
So I'm wondering: Does it save energy if I let the AC run until the room gets cool, then turn it off, then turn it back on when the room gets warm? Instinctively it seems like it would but I don't know if there's some hidden factor that would make me wrong.



We don't have a working flair system yet, so it's hard to appropriately run AskScience, but I can probably answer your question.
The answer is that A/C is most efficient when it is running at an optimal level; the efficiency is related to the compressor more than anything else. Compressors are most efficient when they run continuously, but not flat-out.
The direct answer to your question is that you want to run your A/c at the highest temperature you find tolerable.
Alternatively, a whole-house fan works well, or a dehumidifier, humidity makes things far worse.
Thanks for the answer!
The air flow is really bad in my apartment. The AC, which is basically a window unit installed through a hole in the wall, makes the living room habitable but the bedroom is always stifling even when it's going full-blast. (Which can actually be a problem, since my wife sleeps during the day.)
I've considered a dehumidifier but according to my wife they're overly pricey for what they can get done. The humidity is awful here, though.
So in short... we won't be out an exorbitant amount of money if we have the AC constantly running at the highest setting all day long? Our electric bill was nearly $100 (US) last month :(
You would be better served placing a fan to circulate the air around. The problem is that a window unit is undersized for cooling the area, so it's going to be inefficient. The number of times the compressor needs to kick on is the key.
If the bill is a concern, consider changing to a budget plan which spreads your bill over the year, reducing the peak bills.
What you're describing is a thermostat. :-) Your AC should already have one of these. If not, consider getting one that allows you to set a target temperature. Certainly, running an AC less often would save energy, but I'm guessing that's not exactly what you're asking.
There are also energy waste considerations here around draftiness (which introduces warmer air at a regular rate) and Newton's law of cooling, wherein a cooler house warms up faster than a less cool house. (Rate of flow of heat is proportional to the temperature difference.) I'm not sure exactly how those would play into this.
The AC is provided by my apartment complex. I don't have the money to get a new one.
We did get the landlord to replace the weather stripping on the balcony door when it started getting colder, and that seems to be preventing cold air from getting in. It might work to keep the cool in in summer too; we'll see.