About Duct Envelope Tightness
Have you ever felt like your heating and cooling system doesnt supply to all rooms evenly? Do you feel like you’re wasting money trying to keep your house comfortable throughout the year? Often these conditions are from gaps, and cracks in the ducts which cause air leakage. A duct envelope test is a repeatable and is used to measure duct leakage.
Key elements of a Duct Tightness Testing
Seal All Duct Openings
Whether the ducts are newly installed or part of an existing system all openings in the ducting have to be completely sealed in order to accurately measure the amount of leakage in the system. This is the most time consuming part of the process, has many homes have 15-30+ registers and vents to seal.
Measure Leakage
Duct leakage is measured in CFMs (cubit feet per minute) at 25 Pa. Similar to a blower door test, the duct leakage test will produce a measured CFM of leakage in the total ducting system. Typically for buliding permits, newly installed ducting systems have to pass a duct leakage test.
Current home owners will use this number to compare against a retest after air sealing measures such as aeroseal.
Re-testing
After air sealing measures we can return for a retest. Recreating the same set up as the previous test and comparing the new leakage CFM to the original test. If air sealing measures were affective you should see a large measurable difference in the duct leakage with a lower CFM.
Properties we often audit
- This test can be done on any ducted system
- Repairing Old Duct Work
- Adding new registers to current duct work
- New construction
- New Additions
- HVAC, Exhaust fans, Range Hoods, HRV/ERVs
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What to Expect
Depending on which inspection you’re requesting the time may vary. Pre-drywall inspections typically take under an hour, pre-closing and pre-warranty inspections are typically 2-3 hours. You are not required to be present during any of the inspections, however most home owners enjoy the building process and like to be present for part of the inspection to ask questions.