A year ago I wrote about our deep retrofit project at our 119-year-old farmhouse in Vermont. We buttoned up significantly, reducing air infiltration by 72%, and adding a solar hot water system to reduce our dependence on propane.
Lately I've been wondering about our savings in heating oil, propane and electricity. A quick year-over-year comparison yields the following savings.
We reduced our heating oil consumption 29% although our dollar savings were somewhat offset by the increasing cost-per-gallon of oil. Our dollar savings amounted only to 12% because of a 22% increase in the cost of heating oil.
Propane, which we formerly used to heat hot water, has been the fuel we've trimmed the most. Today we use propane only for cooking. And our use pattern shows dramatic improvement. We reduced our use of propane by 85% in terms of gallons and 73% in terms of dollars. That means the sun's rays have now completely replaced propane as our source of hot water.
Electricity consumption has been the one surprise. I fully expected our kWh consumption to spike since our new solar hot water system has electric back-up. I assumed that we would use perhaps 10-20% more electricity, especially through the winter months when the sun doesn't much shine in Vermont. To my surprise, our consumption of electricity actually declined 7%.
Call it the college daughter effect. The only explanation I can find is that during this past year our youngest child went off to college, which helped reduce our electricity consumption significantly (more than 7%), which was then offset by use of the hot water electric back-up.
All this proves that, if my home is representative, as it likely is in Vermont, there are huge savings to be tapped with a little cellulose, foam and caulk.