Tilson Homes
Aug 6, 2021

Testing to Make Sure Your Home Meets the International Energy Conservation Code

Construction Practices

The International Energy Conservation Code is the set of standards that building professionals must meet to ensure a home meets energy efficiency. Because we want our homes to be as energy-efficient and sustainable as possible, we make sure that they pass two key energy tests before you move in. We run a blower door test, which helps determine how tight your home is and how many air changes occur per hour. Next, we use a duct blaster test to identify any areas in your HVAC system where there might not have been enough insulation installed or there may be an issue with the ducts themselves.

Blower Door Test

The most common way to test the air changes per hour or the tightness of a home is using a blower door test. A third-party energy inspector performs this test and it's done primarily with the use of pressure gauges. A blower door is a door device with a fan on it. The fan blades are calibrated to measure pascals, a pressure measurement, similar to the PSI on a car tire. The blower door is shut and pressurized to match outdoor air pressure, then opened so that the indoors is exposed to this greater force as all of the air is removed from your home. We're simulating 20 MPH winds hitting your home on all sides by depressurizing your home during the test. Air flows out quickly through any leaks in insulation or windows or doors inside the home while the blower door is open and the home is depressurized.

At the end of the test, the inspector will be able to tell us how many air changes per hour (ACH) your home will have and whether we've passed the test. The IECC allows up to five ACHs in Climate Zone 2 and three ACHs in Climate Zone 3. More often than not, the home will pass inspection. If it doesn't pass, we'll use infrared sensors to check the areas of your home most likely to have air leakage - corners, bottom plates, and top plates. We'll seal those areas up with a little bit of polycel and retest.

Duct Blaster Test

A duct blaster test is slightly different and involves pressurizing your home to check the efficiency of the home's air ducts. The purpose of this test is to make sure all the air you're paying to heat or cool is not leaking into the unconditioned space in your attic.

The inspector will hook one of the return airs up to a large supply hose. The hose is hooked up to a fan, calibrated along with the measuring device, to assure a certain amount of pressure. The really important part of the duct blaster test is to create a closed system. So, the next thing the technician does is seal off every supply and return through the entire home to make sure that we have a completely closed and tight system to measure. Once the technician has everything hooked up to the measuring devices, he will calibrate and then start the measuring process to determine the amount of leakage that could be happening in the ductwork in the attic. Using the unit's tonnage, they will calculate how many cubic feet per minute are moving through that system. Using this number, how many cubic feet per minute are lost in the attic as a percentage. The maximum leakage you can have in a new home is 4%, or four cubic feet per minute for every 100 square feet of area. If the calculation comes out higher, we'll locate where the ductwork is leaking, seal it up and retest.

These inspections take quite a bit of time and are a lot of work. But we feel it's really important that the families we build for are getting a very energy-efficient home that's high performing, going to last a long time, save on energy bills, and create a comfortable space for our families.

The Tilson Homes team is always here to help you with anything that you need and we can't wait to hear from you! Take the next step in getting started on your new home by contacting us today. Call (877) 416-2043 or send us an email.

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