Building the NewenHouse Kit Home: The Heat Recovery Ventilation Unit and Insulation Installation

Reader Contribution by Staff
1 / 2
2 / 2

Sonya Newenhouse, Ph.D. is an eco-entrepreneur who enjoys providing practical and creative solutions to help individuals and organizations live and manage green. Her firm, Madison Environmental Group, provides LEED green building and sustainability consulting services. She is also founder and president of Community Car, a car sharing organization in Madison Wisconsin. Currently she is developing NewenHouse, a business that will provide super-insulated sustainable kit homes.

During April and May I was absorbed with Earth Month activities and finishing up my first semester teaching MBA students a sustainability course at the University of Wisconsin. In Viroqua, we had 100 guests attend our Earth Day NewenHouse OpenHouse. Now I’m back to the blog and sharing pictures and videos with you. Thank you for your patience.

The windows are installed, the insulation was blown into the 16-inch-thick walls, the drywall is hung and now the painter Jim Green is busy painting the inside of the house before the local ash flooring and trim get delivered. David and Dan are busy installing siding and working on the detached porch storage room on the north side of the NewenHouse. I’m busy finalizing custom cabinet details, ordering tile, and sourcing brightly colored eco-friendly upholstery material. Cecil has a couple of wingback recliner chairs that are not modern enough for my liking, but they sure are comfortable and he likes them, so we agreed to re-cover them in fun, bright material.

The windows are installed and the cedar siding is partially installed. Photo By Sonya Newenhouse.

After the windows were installed, David and Dan installed the HRV (Heat Recovery Ventilation) unit. It’s a Zehnder, made in Holland, and it’s Passive House-certified and highly efficient (92 percent). Because our house is small we wanted to get a quiet and highly efficient unit. We installed it in the closet of the guest bedroom on the second floor. Carly Coulson and Barry Stephens (President of Zehnder America) figured out a design to ensure we were adequately bringing fresh air into every bedroom and living area and exhausting the kitchen and bathrooms. With an HRV system, you don’t need extra bath or kitchen exhaust fans. 

The HRV is like the lungs of the house, breathing in fresh air continually. It’s a critical feature to the performance of certified Passive Houses. When you build a house as tight as the NewenHouse, you need to ensure that you have proper ventilation. The HRV will run from October to April, and in warmer months we hope to use natural ventilation. The window placement was designed to create a chimney effect for cross ventilation. 

Sonya describes the HRV (Heat Recovery Ventilation). Video by David Romary.

We conducted a Blower Door test prior to installing the insulation to make sure the house was tight enough to meet Passive House standards (less than .6 air changes per hour at 50 Pascals). The Blower Door device didn’t suffice for such a tight house, so we used a Duct Blaster technique instead to preform the test. Laura Paprocki, our Green Rater from Madison, Wisconsin, performed our test. It’s a good idea to conduct a Blower Door test at this time in construction so that you can fix any leaks before insulation and drywall are installed. It would be much harder to find and repair leaks afterwards. Our test was successful, but sure enough we still found some hairline cracks to fill.

Laura Poprocki describes the Duct Blaster test. Video by Sonya Newenhouse.

Next, Warm House insulation contractors arrived with their insulation equipment and a huge delivery of cellulous insulation (recycled newspaper from Wisconsin). They dense packed more than 200 bales of insulation into our walls to create an R-value of 57. They also installed 8 inches of insulation into the ceiling system and will return to add another 16 inches in the vented attic to create an R-100. Dough Hirsh of EverGreen Drywall and Plaster hung drywall on the ceiling and left a few openings for the insulation to be installed. Next the Warm House crew stapled insulation fabric on the walls then hooked up their insulation hose and blew in the shredded recycled newspaper into the wall cavity. 

Sonya describes the insulation installation. Video by Jamie Cermak.

It’s tricky to install the insulation so that you don’t over-insulate the walls, which would cause the drywall to bulge. We used a thicker drywall (5/8″) to alleviate this problem and also for sound proofing. In addition, the extra-thick drywall adds strength to the wall system, which was built 2 feet on center instead of every 16 inches. This technique saves lumber and reduces thermal bridging. The new home is already noticeably warm. We’ve had a very cold long spring (in the 30s most nights) in Wisconsin and it was wonderful to walk from our current home built in the late 1800s and heated with a furnace and wood burning stove into our new home and notice such a vast difference in temperature–and we don’t even have the doors installed in the NewenHouse yet!