February Follow up on Green Technology that pays for itself

Two months ago I wrote in Follow up on Green Technology that pays for itself that by my calculations the extra insulation I put in the ceiling resulted in a 10.2% drop in kilowatt hours and a $29.78 drop in the total bill. Earlier this month I looked at the January electric bill and said I was disappointed when I found only $7 of savings. I just received this months bill and this month’s bill is $115 lower than last year and I found an error in last month’s savings calculation. Last month’s savings attributable to insulation is now $34 and this month’s savings is $58. My favorite metric, the ratio of Average KWH per day over the Average Heating Degree Day is now solidly under 4. Here is my updated graph using some forecast data for 2012

2012 Goshen Heating Regression