#6 Wrapping It Up…Steps to Building an Energy Star Home
In the current series of articles, we chronicled the steps to building an energy efficient home based on a current project here in Flagstaff. We just finished a house for a professor north of NAU who decided to prioritize energy efficiency. The previous articles covered the basics: getting out of the ground, waterproofing, insulation, radon, wall types, air sealing, and mechanical systems. This article will wrap it all up and have our professor ready to move in!
Now that we are arriving at the end of our six-month journey from inception to completion, we need to verify that what we built was what we said we would, and that the home will perform the way it was designed. If you remember from the first article, we designed this home with a focus on energy consumption. We used a third party energy rater, “E3 Energy,” right here in Flagstaff to model the home during the design phase to forecast the energy costs over the life of the home. That process helped us identify where we wanted to focus our resources to get the most return. Now it’s time to see if it will all pay off. To test a home at the end of construction, the energy rater comes back out and does a final “blower door test.” They set up a large fan in one of the exterior doors and depressurize the home until they reach a certain internal pressure. The data that is collected from the test is put back into the energy model and verifies if the home will perform as designed. In our case, the home had a blower door number of 700CFM 50, which fell right into the design criteria.
The whole house is then graded to see where it lines up against other homes. The grade is called a HERS score, and ranges from 150 for an existing house, 100 for a code built house, all the way down to 0 for a home that creates as much energy as it uses. This house ended up with a HERS score of 59, which puts the home about 40 percent more efficient than a code built home. Once the testing is completed, the energy rater will forward the results to the EPA for ENERGY STAR labeling. This particular home also participated in the Coconino County Sustainable Building Program, and after a final four hour inspection and interview, it passed their performance criteria and is considered certified.
Believe it or not, one of the last steps before we turn over the keys to the home is to show the customer how it works! We provide an owner’s manual for all of the equipment, lighting, and mechanical systems in the whole house, and show people how to make adjustments that will affect the performance of those systems and the home as a whole. When people understand how the different systems in the home all work together, they tend to live a little bit more efficiently. It almost becomes a game to see how little energy they can use. After it’s all done, it’s time to move in and enjoy the comfort and savings! FBN
You can follow the progress of the home on our blog at: http://hopeconstructionaz.blogspot.com/.
David Carpenter is the owner of Hope Construction, a general contracting and construction management firm with an emphasis on sustainable building. He can be reached at 928-527-3159.