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WHAT IS THE BEST WAY TO SAVE ENERGY WITH WINDOW AC?
Question by Bethany P:
What is the ideal way to save energy with window AC?
My roommate and I are having a tiny “disagreement” about our window AC. I like to turn off the AC when I leave the apartment to save energy. She likes to leave it on all day on 73 because she thinks that it saves energy and she is hot natured and doesn’t like the apartment hot when she gets home. Please tell me that she is wrong.
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Answer by bugear001
She might be right. If the unit has a thermostat setting she is right. That will grant the compressor to turn off when the 73 setting is reached. The fan will still run. When the room warms up, the compressor will kick in and cool the room back down. If it does not have a thermostat, the compressor will run all the time and use more electricity. If your unit is fairly new, it has the thermostat setting on a LED readout.
Turning it off during the day will cause the compressor to run longer to reach the 73 setting,,,using more energy.
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about 1 year ago
You two might compromise by setting the thermostat higher when you’re both out. Turning it completely off means the temperature of everything in the apartment will rise while you’re gone. It then takes more energy to cool everything back down again.
about 1 year ago
You know she is wrong. For an apartment, how long does it take to cool the living space? Perhaps 10-15 minutes. Leaving it on 8 hours to shorten 15 minute wait is wasteful. That is like leaving the car running with the AC on so that it would be cool when you are ready to drive. Unfortunately, some people do that as well.
Even with a thermostat, the compressor will still be running longer and using more power. A house never has perfect insulation. Even with a thermostat in a very well insulated house and the thermostat set at 80 when it is 90 outside, the compressor may be on 20% of the time. Over 8 hours, that is over one and one-half hour of the compressor at maximum. And most apartment aren’t well insulated. With the thermostat set at 73, the compressor might be on half the time. (You can time it yourself).
A window unit with 6000 BTU/hr cooling capacity will cool a 250 square feet room with 9 feet high ceiling from 90 degrees Fahrenheit/80% relative humidity to 73 degrees Fahrenheit/50% RH in less than 10 minutes.
http://www.consumerenergycenter.org/home/heating_cooling/window_ac.html#Figure
about 1 year ago
Any unit that can cool an apartment down to comfort levels in 10 to 15 minutes is way too big for the job. A properly sized window ac unit will drop the temperature in the area about 2 to 3 degrees per hour, if started with the room at the same temp as outside. When the unit is turned off completely, the space not only gets warmer, but humidity infiltrates from outside. The moisture in the air also has to be removed when the unit is started in order to reach a comfortable condition. If the room is empty for 4 or 5 hours, it’s best to leave the unit running and raise the thermostat setting to about 78, to keep the humidity under control. If you’re both out for 8 or more hours, and you live in a fairly dry climate, then turning the unit off completely will be less costly in the long run.