Net zero homes are about the details. The accumulation of these details, of these seemingly small changes to the homes’ building process, multiplies the homes’ efficiency and comfort. To build these homes, Green Canopy has cultivated a vast system of checks and balances both originating from within the company and from partners of the company. The team at Green Canopy’s net-zero home in Magnoliarecently completed one such check: the blower door test.
There are well-known frustrations with homes built in the 70’s and 80’s that were sealed up very tight with little thought put into proper ventilation. Without that proper ventilation, the airtight homes get moldy and begin to rot. When talking about making our homes airtight, people often have reactions associated with these mold-prone homes in the past, but the contemporary phrase in the industry is to "seal up tight and ventilate right." With proper ventilation, we can get a temperature-controlled environment without the negative side effects. The home's structure is set up to last with a Heat Recovery Ventilator that reduces pollen and dust giving the home constant fresh air. The ventilator also takes the stale air from inside the house, recycles the heat, and joins it with fresh air from outside.
In the test, a blower door machine is mounted to an opening such as a door or window. A large fan located at the lower end of the blower door depressurizes the space behind the machine, and the ACH—air changes per hour—of the building can then be calculated with the help of the blower door’s manometer. Because the room is depressurized, the air is forced in through small cracks in the house's structure that would otherwise be invisible. With the smoke test and other tests, these air leaks can be found and sealed up, and homebuilders can create a more airtight home.
Most new construction homes do not undergo the blower door test, but those that do usually only manage to reach an ACH of 3 or 4. At completion, Green Canopy’s net-zero homes will have only 1 ACH. The difference is in the timing. Instead of conducting the blower door test when the home is nearly finished as many homebuilders do, Green Canopy enlisted Performance Insulation to conduct it during the framing stage, giving the team the ability to find and fill more of the house's air leaks. The goal is to seal the leaks up tight in the home, then add the proper amount of controlled ventilation to the home.
With so many of the air leaks in the house filled, less heat is needed to warm it, increasing efficiency and decreasing costs. This one detail, though it may seem insignificant, combines with others to create a home efficient enough to become net-zero after the installation of solar panels. Green Canopy’s goal in building net-zero energy homes is to help spark a transformation toward a more sustainable and resilient housing market.