Sunday, August 12, 2018

Summer time power use for 2018!

Forsyth MO: It was august the 12th and so I was arguably in late summer. I thought it might be of historical interest (at least to myself) to take a gander at the power use curves I was experiencing.

Following are the ground parameters:

Space to be cooled = 900 square feet with a volume of about 7,200 cubic feet.
3.5 ton 2 stage AC unit set to maintain 81F.
Blinds were generally closed.
Normal power use items always on - Computer equipment, fans, flat screen TV
Power appliances cyclical: water heater, refrigerator
Occasional use: Convection stove top, microwave, washer and dryer

The following scatter chart reflected energy consumed as compared to the average outdoor temperatures over a period of 8 days where the daily highs ran a gauntlet from 88 up to 96 degrees. Nighttime temperatures averaged from 60 to 68F. In other words a pretty typical period with partly cloudy skies thrown in for good measure.

Click to enlarge
Understanding that my baseline of power use (ie the average consumed with no AC used) was at about 14 kilowatt hours a day, the trend line that was generated using a scatter chart (avg temp vs kwh) correlated rather well. My average daily use of 25.5 kWh's indicated that my electric bill was going to be ((25.5*30)*.13006) +15 or $115. Not too bad as the average internal temp in the condo ranged from 81 to 84 degrees. Note that whenever the average daily temp drops below 74 degrees, I normally have the AC turned off and so follow a power use level that results in electric bills below $100.