Structural Insulated Panels as a Roof at Far Reach Home

5 Star Built Green EERE’s Builder’s Challenge (HERS 39 rating)

Energy Star Certified

EPA Indoor airPLUS Qualified Home

Silver EVHA Award

Square Footage: 2100ft²

Matt Cooper and Eileen Ryan wanted to build the most cost effective energy efficient home they could, so they turned to Scott Bergford of Scott Homes, Inc. Scott Homes has built with Structural Insulated Panels for 18 years and is very familiar with their level of performance. However, the company had never used the panels in the entire envelope. Scott struck a deal with the Matt and Eileen where, if he could experiment by building their house entirely with SIPs, including floor, walls, and roof, he would absorb the extra cost of the thicker SIPs. Washington State University Extension Energy Program was brought in to study the project and record the performance of the house.

Before a design could be settled on or even permitted, Scott Bergford spent time educating the permitting department he’d have to work with. He met with engineers and building scientists to educate himself and the plans examiners on how a house like this could be built, be structurally sound, and meet all relevant code requirements.

The home’s envelope is comprised entirely of SIPs, making the whole house conditioned space, including the attic spaces. When a blower door test was administered, the results showed .65 ACH50, or .65 Air Changes/Hour at 50 Pascals, a result just above the industry’s most airtight method of construction, the Passiv Haus(r). To meet Passiv Haus standards, a structure must show .6 or less ACH50, meaning the Far Reach House is not far off.

The residents are very pleased with the finished home, as it is extremely airtight and very cozy. According to the residents the daily operating cost averages $3.20/day. Energy use is lessened by simple activities like cooking or having guests over, both of which naturally heat the home.

The house has been rated 5 Star Built Green, it meets EERE’s Builders Challenge (HERS 39)rating, is Energy Star certified, is an EPA Indoor airPLUS Qualified Home, and will be receiving either the Silver or Gold EVHA award in Feb 2012.

After construction it was shown that the 12 inch panels used for the roof were in fact too thick and therefore were not as cost effective as a slight thinner panel would be. The extra cost is not accounted for by the extra thickness.