Why does an air conditioner use so much electricity?

Question

Before you classify this as a stupid question, think of this. The small motor that turns the fan at the top of the unit is maybe 2 amps and uses about 20 dollars worth of electricity in a month, if that much. However, the compressor makes my electric meter spin like a wild top out of control. Running the air conditioner makes my electric bill increase by roughly three hundred or more dollars each month --- or more. By the way, my unit is only eight years old. Does anyone realize that true wealth and prosperity beyond imagination await the man that invents a genuine energy-saving compressor? So here is my real question : What the heck is in a compressor that sucks the electricity like a vampire? What could possibly be inside a compressor that uses so much juice?

Answer 1

TOO LATE
The scroll type compressor saves energy, lasts longer, and is much quieter.

Answer 2

Two things:
1. A compressor is a pump which consumes a lot of power - you are compressing a gas into a liquid in order for the cooling to occur. The cooling fan which blows the air into the room consumes negligible power (maybe 150 watts/hr.)
2. The motor driving the compressor is not 100% efficient.


For grins, say a 28,000 BTU a/c unit uses 14.6 amps at 230 V (a Sears unit) and you set the temp setting so it runs 50:50 duty cycle during the day. It's off from 8pm to 8am.

Let's say the compressor has a motor which is 80% efficient, that is 20% of the power used by the compressor is lost to friction in the motor, etc.

So, in a 24 hr day, you are consuming approximately: 12 hrs x 7.3 amps x 230 volts / 80% = 25,185 watts of power, or 25.2 KW. At $0.30 / KWhr, that's $7.55 per day of electricity, or $266.67 / month.

(A 110 V a/c unit will consume more power than a more efficient 230 V unit.)

To save money, you can get a 230 V unit, or raise the thermostat temperature. The a/c unit will use the compressor less often, and blow cool, but not cold air.

Make sure your A/C unit is well-cleaned inside - vacuum the dust off the cooling coils and make sure your filter is cleaned.


Not much more can be done to improve a/c units except to use high efficiency motors. For the price people are willing to pay, the compressors are pretty efficient. And the cooling fluids used today don't have many options because of the regulations for CFCs.

Answer 3

Window units are designed to cool small areas, not usually the whole house. If the filter is noy cleaned or replaced on a rehular basis it has to weork harder. The harder is works the more energy it has to use. Plus if you have it running a an extreme low temp. it can't stop. Try to find a comfortable setting and leave it there for a while. Besides, that is most likely NOT the only thing that is using ALL the electricity. Find ways to use less. Try using the "mini twist" flueresent bulbs the fit where regular light bulbs are used.

Answer 4

8 years with 0 maintenance may cause the wild spinning in your electric meter. also, check your temperature settings. you setting might be higher than what you just need for comfort cooling. also, the thermostat may no longer we working. have it checked for efficiency - call your a/c technician.

Answer 5

8 years is about the life of air conditioners, so it is going to be less efficient.

Answer 6

use a Fan its only 30 watts