Zero Energy Home: The Bottom Line

I've posted in the past about the elements that went into our energy efficient house (which we hope will be net zero energy). I've also talked about how the weather and use of appliances, electronics, and other consumers of electricity affect the performance of the house. But what it really comes down to is one question: “How much money do you spend to heat, cool and power your house?” I don't have a complete answer -- yet -- but I can tell you that our electric bill for the December/January (mid-month to mid-month) period was $3.64.

No, I did not forget a digit or misplace a decimal: three dollars and sixty-four cents. And we don't have any natural gas appliances in our home, so no gas bill. I've talked to some of my friends at work, and they indicated that their most recent electric bill was on the order of $100. And they have gas furnaces, so that number doesn't include the thermal energy needed to heat the house. I'd also like to point out that the period also includes the year's shortest days, and quite a few cloudy ones, too, so we're not generating peak electric power from our solar array (5kW dc, in case anyone has forgotten).

On the other hand, we were on vacation (out of town) for about a week during that period, and had our programmable thermostat set to vacation mode (we set it at 55 (F) to heat the house and 85 (F) to cool the house). That makes a significant difference in the amount of energy consumed during that period, which is why I can't quite bring myself to claim that we were net zero energy, yet. Plus we have to get through the hot summer months. But I think it's encouraging.

And I love to show off my $3.64 electric bill. It makes me feel so smug.