Wednesday, August 20, 2008
In addition to the LEED certification program, we also enrolled our project in the Triple E Construction/Energy Star program through our utility provider Minnesota Power. This program rewards energy efficient construction techniques by verifying the thermal performance of the house and awarding cash rebates when certain levels are achieved. To verify the energy efficiency of the barn, a blower-door test was conducted. This procedure consists of sealing off the doorway with an expandable frame and fan assembly that depressurizes the building by blowing air out of the house. As the building is depressurized, air will rush in through the various "leaks" in the walls, penetrations, windows, etc. Sensors on the blower unit measure the amount of airflow required to achieve a given pressure level- the "tighter" the house, the lower the flow. While the blower door test was running, I got to walk around with the thermal imaging camera, which displays the temperature variation in the surfaces of the building. If any air was finding its way into the house, it would show up as a "hotspot" on the camera. Pretty slick tool! I have been anxiously awaiting this test for months, and can now say the results were even better than I had hoped for. The little white barn was super tight- the air infiltration was so low that we could not get an accurate reading with the blower door test! He will need to come back to retest it with a more precise blower setup before we can know for sure, but for now it looks like we may be building the most energy efficient "barn" in the world...and a rebate check is on the way (finally, greenbuilding pays!).