Priority Energy, IECC Duct Testing, IL

Duct Leakage Tests and Same-Day Reports!


Duct Tightness Test (IECC 2015 Section R403.3.3)

Since 2009, under the IECC Code, all ducts should be sealed, air handlers sealed, and duct tightness should be verified by a duct leakage test unless 100% of all ductwork is within the conditioned space. This means that any time you run a duct outside of the building envelope (in the attic, crawlspace or garage, for example), the system has to be tested.  It is not an easy test to pass, click here to see results from accross the Chicagoland area.

There are two times during construction at which the ducts can be tested:

1. Rough-In Test

This test happens before the air handler or registers are in place (typically before drywall). The requirement for IECC 2015 is 3 cubic feet per minute (CFM) of leakage (at 25PA or 0.1IWC, the normal operating pressures of a duct system) per 100 sq ft. of conditioned floor area where the air handler is installed at the time of the test. This means you will get 3 CFM of leakage per 100 sq ft that the air handler serves.

We recommend performing the duct test during the rough-in stage of construction, because while 4 CFM/100 Sq Ft may seem like a lot, it’s a very small amount.

Example: if you have a HVAC system serving the second floor of your house with the ductwork running in the attic, and the second floor is 1,400 sq ft, only (1400/100 x 3) 42 CFM of leakage will be allowed in the duct system. This is not a lot when you factor in all the connections in a typical duct system (take offs, elbows, boots, cleats, etc.). It’s also easier to address any issues at this point since the drywall has not been installed, so your ductwork isn’t yet concealed.

2. Post-Construction Test

This test happens after drywall and all registers and air handler(s) are in place. The requirement for IECC 2015 is 4 CFM of leakage at 25 PA/0.1 IWC per 100 sq ft of conditioned floor area.

While you may be thinking this has increased the amount of available leakage (56 CFM from our previous 1,400 sq ft second floor example), we do not recommend testing at this stage. This is primarily due to the fact that virtually all of the ductwork is concealed by drywall and insulation, the air handler is in place (which can leak as much as 100 – 200 CFM by itself), and the registers are in place, so we will also be taping over these and testing the connections between the boot and subfloor/drywall. While it is possible to test and pass at this point, it is much more difficult because the majority of ductwork is concealed or hard to access. Your only option may be Aeroseal at this point.

In addition to the required duct testing, Priority Energy also provides Aeroseal duct sealing, which is a guaranteed way to pass your duct leakage test. In one easy step, we’re able to provide a test and seal at the same time--this is an IECC/Illinois-recognized method of testing and sealing.

Priority Energy is pleased to provide a solution for all of your duct testing and sealing needs. Give us a call!

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