It's time to stop energy loss
If you’re building a new energy-efficient home, making sure your insulation is installed correctly should be front and center, and doing so can make the difference between “pretty good” and “exceptional.”
Take a super-insulated net-zero home that was recently completed in Spring Green, Wisconsin, for example, where Accurate-Airtight Exteriors’ insulation work played a crucial role in its success. Over the course of 7 days, a two-man crew pumped 12 inches of dense-pack cellulose in the home’s double-stud walls and 22 inches in the vaulted ceiling—one of the thickest insulation installations yet for our company.
Plans and uber-airtight construction details were prepared by Amber Westerman Building Design and executed by their construction company, Poem Homes. When our insulation work was completed, blower door testing revealed an ultra-low 0.70 ACH@50Pa reading, which means this house can truly serve as a demonstration home for sustainable building methods and materials.
Accurate-Airtight spares no expense when it comes to insulation and air sealing details, and when it comes to seriously airtight homes, those details make a big difference in air infiltration rates. At the exterior walls, the plywood sheathing was taped and all mechanical penetrations were flashed and sealed to a drainable housewrap to prevent water intrusion and inward moisture drive. Below the roof, a 2-inch ventilation channel was built into the truss assembly to promote drying across the top of the ceiling cellulose.
Inside, the walls and ceiling were draped in a variable perm vapor retarder, sealed at all joints and mechanical penetrations. The drywall was then installed as usual except for an 8-12 inch gap at the top of the walls, below each window, and down the center of the ceiling—just enough space for Accurate-Airtight's blower hoses. The crew worked steadily, packing the wall and roof cavities so thoroughly that by the time they were done they had the look and feel of a firm mattress. They sealed the vapor retarder with builder's tape as they progressed. Later, the gaps were covered with drywall to create a continuous air barrier.
While in the planning stage for this home, Amber stopped by Accurate-Airtight's booth at the Midwest Renewable Energy Fair in Custer, Wisconsin. There she met Torrance, the company's owner, and learned that their cellulose insulation has some serious green cred. The insulation material is sourced from nearby Fond du Lac and is made from 85% recycled content—including wood fiber, boric acid, and starch, all benign, biodegradable materials that pose no threat to the environment.
At R-45 for the walls and R-82 for the roof, the insulation value of the home is more than double code minimum and will retain its integrity for the life of the building. The air changes per hour at 50 pascals measurement this home was able to achieve after A-A’s insulation installation puts it in the top tier of energy-efficient home performance, minimizing air infiltration and maximizing energy savings for the owners.
The new construction home is expected to be very comfortable and use very little energy compared to a conventionally built home. Energy use will be monitored over the next several years by our team of building scientists and home energy auditors and should prove that spending more upfront on insulation and air sealing is a smart bet against rising utility bills.
Dense Pack: Take 1 | POEM HOMES
Dense Pack: Take 2 | POEM HOMES
Just a quick note about the air sealing that you did in our home. It has worked as you indicated that it would. We noticed an immediate improvement in our basement. We obviously had some problems in that area that one would not normally associate with a nine year old home. The temperature in the basement is now much more comfortable and the kids seem to play down there more often.