Air Conditioner Power Consumption

How much electricity does an A.C. use and how much does it cost?

by Don Ames

The window A.C. unit is very common

An Air Conditioner can seem like a very important appliance when the temperature outside is 102 degrees. In that temperature, the A.C.can run a long time. What is the air conditioner power consumption and how much does it add to your electric bills?

To get an understanding of air conditioner power consumption, we need to look at the rated BTU’s of cooling output and the associated number of watts used when the A.C. is running. This is like a light bulb, you know, a 60 watt bulb gives off less light than a 100 watt bulb. The 100 watt bulb uses 100 watts in an hour and the the other bulb uses 60 watts in an hour.

The BTU rating will tell us how big the air conditioner is and how big of an area it will cool. Room air conditioners can have a rating of 4,000 to 12,000 BYU’s. Whole house, central air conditioners can have an out put rating of 20,000 BTU’s and more. Larger homes can be over 150,000 BTU.

The higher the BTU rating the more watts it takes to operate the air conditioner. One advantage of having a well air sealed and insulated home is the fact that the home can be cooled using less BTU’s. The A.C. unit can be smaller and the air conditioner power consumption will be less.

To maintain a cool house and to do it with fewer BTU’s and less power consumption, the attic thermal barrier needs to perform. If the attic gets super hot and then easily heats up the living space, the air conditioner power consumption is going to be high. If the attic is separated from the living space with an effective thermal barrier, then the air conditioner BTU rating can be reduced and power savings result.

Portable and Free Standing

Power consumption of a room air conditioner

A room air conditioner would be a portable, freestanding model or one that is installed in a window opening. This sized A.C. is often rated about 12,000 Btu and uses 1500 watts per hour. If you use this air conditioner 200 hours per month it will use  300 kilowatt hours of electricity. At 11.5 cents per kWh that’s $34.50 per month.

To find the number of watts the unit uses per hour, you will need to get this information from the product sticker on the unit or from the product specifications that can be found online.

Air conditioner power consumption of a whole house air conditioning system.

This is the large box looking thing that is sitting behind your house with the fan in it. This outdoor air conditioning unit is connected to the furnace by a couple copper refrigerant lines. The larger refrigerant line should be covered with insulation.

Air Conditioner, 36,000 Btu, 4500 watts, used 200 hours per month uses 900 kilowatt hours of electricity at 11.5 cents per kWh, thats $103.50 per month.

Now that you know about air conditioner power consumption, you can plan ahead and find ways to conserve energy and lower your power bill.

Thank you for stopping by, hope your staying cool, come back soon, but I won’t leave the light on for you…

Don Ames