Quote:
Originally Posted by stevehull
You are right about the therm reduction (60.8 to 51.0 =-16.12). However the reduction of degree days is 1029 to 911 = -11.47.
So , despite a decrease in the heating load of ~ 11.5%, there was a reduction in gas usage of 16%.
Maybe that difference was where the 5% reduction came from . . . .
Steve
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I want to provide some clarification on my measured 5% decrease in Natural Gas usage.
I compared natural gas use for the same billing period (Jan / Feb.) bill for the year before and after I installed the programmable thermostat. I then pulled the Heating Degree Day data (from wunderground.com) for the same days as the billing period for each year. Then I divided the Therms of Natural Gas used by Heating Degree Days (Therms / H.D.D.) to compare the difference the programmable thermostat made.
Therms of Natural Gas used per Heating Degree Day was the point of comparison that showed the 5% reduction in Natural Gas used. There is probably a more accurate way to calculate the difference, but not with the tools that I have.
I hope that helps,
Tim