1000

I came home this evening and noticed as I passed the meter for the Fujitsu heat pump that it's just turned over 1,000 kWh since we switched to the heat pump for heat the day after Christmas. During that time, we've experienced about 3,250 heating degree days base 65˚F (HDD65 ) A degree day is a measure of heating demand, in which the average temperature for the day is subtracted from a base temperature, traditionally 65˚F. This is about 55% of a typical annual HDD total for Martha's Vineyard, and since 300 or more of those HDDs occur June - September, when the heat isn't on, it's even a bit higher. I'd expect to use more heating energy during the first half of the heating season, because of lower solar availability - December and February have similar average temperatures but there's more sun in February. This effect isn't as powerful in House 5 as it was in Nerdwood, back in Meriden, because the NH house had more south glass and less shading. Nonetheless, I think it's reasonable to say that we might expect to heat the house for under 2,000 kWh annually with the heat pump. I like this better than 300 or so gallons of fuel oil.