Duct Sealing and the Duct Leakage Rate

Energy Star reports that for any given house "about 20 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts. The result is higher utility bills and difficulty keeping the house comfortable, no matter how the thermostat is set".  

Given the amount of heating and cooling that is typically lost in a heating and cooling system, reducing the duct leakage rate is a crucial part of the reducing the energy load of a building. 

For us, that means a few installation quality requirements for our subs:

•  Mastic, no tape!

•  3rd party duct testing is required

•  Preliminary and a final duct testing

•  Guarantee a total leakage rate of less than 6%

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What is a duct blaster test?

A duct test pressurizes the entire duct system in a house and measures how much air leaks.  To do this, all parts of the system must be in place and sealed.  Then a fan is connected to the system and a pressure gauge to calculate how much air is lost.

We do a preliminary test prior to insulation and drywall to ensure no big holes have been missed, and then we do a final test post drywall to assess the final leakage rate.

The picture shows are Green Rater, Andy from Elysian Energy performing our initial duct blaster test.  The system is pressurized with a fan and he is checking the overall pressure and leakage.

The images the right show sealed registers and returns…this is how you seal for a duct blaster test!