The summer is coming up and I have to consider the air conditioning in my apartment. When I was living in the trailer over in Harding Woods there was central air conditioning. However that broke down around 2010. And for the next 7 years I had a 12,000 BTU unit for the front half of the trailer, and a small 4,000 BTU window air conditioner in the bedroom. It was never really enough to cool the place, but it did render the trailer semi-comfortable.

Here in Buena Gardens Senior Apartments there is a 12,000 BTU wall unit, basically the same unit that is over in mom’s apartment at Baker Place. Mom’s unit works very well for her 400 square foot apartment, but her’s is 10,000 BTU. My apartment is 650 square feet.

Last week there were two days at 89 degrees one day and 90 degrees the other, so it was at that time I turned my unit over to Air Conditioning and checked the unit out. It did run just fine. But next I wondered just how much it would cost to run the unit. So that left the question just how to calculate that?

Luckily when the unit had it’s heater half repaired I had taken a picture of the plate. And on the plate it told me that the cooling amp load was 5.1 amps at 240 volts. So it was just a matter of doing the calculations:

- 5.1 amps times 240 volts = 1,224 (amp-volts = work = watts)
- 1,224 watts divided by 1,000 = 1.224 KwHrs
- 1.224 KwHrs times $0.2024 per KwHrs = $0.2477 per hour
- $0.2477 per hour times 24 = $5.94 per day
- $5.94 per day times 30 = $178.37 per month if running continuously
- if running 50% of the time then monthly would be $89.19
- if running 40% of the time then monthly would be $71.35
- if running 33% of the time then monthly would be $58.86

- I Love Math! (could you tell?)

So the next thing I need to do once we reach the summer in earnest is to measure what percentage of time the unit runs at different ambient temperatures. They I will know just how much of my electric bill is going to cooling.

For the time being I have the thermostat set for 76 degrees, since I find that completely comfortable.