How does your house compare with other houses in heating efficiency? As outlined in the previous post, figuring out how much energy your house uses for heating is relatively easy. An average house will use 10,000 to 15,000 Btus per heating degree day (HDD). But this measure alone doesn't reveal how your house ranks on the scale of heating efficiency, and doesn't help determine if there is lots of room for improvement or if you've got your house about as efficient as it's likely to get. A refinement is to determine the energy used per square foot of living space, and compare with the range of houses. The chart here, adapted from the book Residential Energy: Cost Savings and Comfort for Existing Buildings, by John Krigger and Chris Dorsi, shows this range.