The Bellevue Cottage Graduates Summa Cum Laude

On September 17, the 1st Bellevue Cottage at Oak Park received its "Energy Efficiency" degree from the good (but tough) folks at EarthCraft Virginia.

The picture to the right shows the cottage undergoing its final exam. Bob Congdon, our EarthCraft Virginia-assigned energy efficiency inspector, is performing a "blower door test" on our cottage. Essentially, Bob closes up the house completely, with the exception of a special fan that allows him to alter the air pressure in the house. By altering the air pressure in a controlled way, Bob can accurately measure how much conditioned air leaks from the house (these leaks, of course, are the primary causes of energy innefficiency.)

The bottom line for us--we had an extremely low level of leakage, one of the best Bob has seen. We'd passed our final exam, and now Bob and his EarthCraft friends went off to determine our final grade.

By combining the results of the blower door test as well as inspecting various other features of the house (such as the efficiency of appliances used, levels of insulation, window performance ratings and many more), Earthcraft Virginia gives each inspected home a "HERS Score". The HERS Score is essentially like a gas mileage figure for your home. It was developed by the US Department of Energy and is the standard used by independent, certified energy inspectors across the country.

Homes “built to code” are given a score of 100. Homes built to a higher energy standard receive scores below 100, with each point below 100 representing 1% less energy usage when compared to a standard new house.

Based on our construction methods and materials (and the "tough but fair" oversight provided by site superintendent Richard Smith), the Bellevue Cottage received a HERS Score of 49, which suggests that energy usage in our home will be less than half that of a comparably-sized new house (and even less compared to older or oversized houses).

We still have some final work to complete as we strive to build a home that is both smart and beautiful (why not stop by and take a look?), but we feel as if we have graduated from a very tough school. Quite frankly, we are very proud of ourselves, and know that the Cottage's future owners will be proud of their very low energy bills.