Lake Quivira Passive House - Preliminary Blower Door Test

The Prairie Design Build team is excited to bring the first Passive House retrofit to Kansas City, the Lake Quivira Passive House Project.

David Hawkins, our Building Scientist, completed an preliminary Blower Door test to measure the leakiness of the home and pinpoint the leak locations. Our findings were just as we expected - this is one leaky 50-year-old home.

Watch the video below to see David Hawkins perform the test, find leaks throughout the home, and describe the findings:

To perform the Blower Door test, we first close all exterior windows and doors, open all interior doors within the home, and turn off all mechanicals. After setting up the Blower Door in one of the main entries, we take measurements from two different portions of the test - pressurization and depressurization. Our goal is to change the pressure in the home from positive 75 Pascals (Pa) to negative 75 Pa. The software takes readings and derives a calculation for the amount of air leakage in the home.

The pressurization portion of the test consists of blowing air into the home through the Blower Door from the outside. Depressurization occurs when we blow air to the outside from inside of the home through the Blower Door. By doing this, we create a pressure difference between outside and inside the home. Nature wants to always have equal pressure, so to relieve this pressure difference air moves through penetrations in the building envelope. These penetrations could be from any number of things, including: spaces between the exterior doors and frames, cracks between the window frame and buck, electrical outlets on exterior walls, and even directly through exterior walls.

We measure the test using a unit called ACH, or Air Changes per Hour, at 50 Pa. Essentially, this number describes the amount of times your home will recycle all of the air inside your home with outside air at 50 Pa of pressure. 50 Pa of pressure is roughly the same amount of pressure as 20 mph winds blowing on your home from all sides. Typical new construction in the Kansas City area varies between 5-10 ACH50.

Unfortunately, due to the leakiness of the home, we weren’t even able to get to 50 Pa of pressure difference. However, using a best-fit line, we were able to derive an estimate for the project.

To be Passive House certified, our Lake Quivira Passive House must be at or less than 0.6ACH50. Our initial Blower Door test garnered a result of about 15ACH50 -  much higher than typical new construction, and much much higher than Passive House requirements. We certainly have our work cut out for us to get this home to Passive House standard.