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The Duct Tightness portion of the mandatory “DET Verification” requirement only applies to the entire HVAC system and duct work that is not completely contained inside the buildings thermal envelope.
This testing is commonly referred to as a Duct Leakage or Duct Blaster Test. Depending on which Compliance Path you chose when initially pulling your permit will determine the allowable leakage – is it 4% or does it just needs to be tested? (i.e. don’t make a $1500+ mistake)
To schedule a duct &/or envelope leakage test please call us at (815) 200-3688 or send us an E-Mail — FYI, we don’t simply give you your result & bolt; we include up to 30 minutes for diagnostic time which allows for additional sealing work to be completed before getting you your final result. If additional time is required to pass & our schedule allows, that time will be billed out as Diagnostic & Training Time, saving you not only time later but a retest fee.
As of July 1st 2019, the only change made from prior codes is that the Building Department / AHJ may require an independent third party to conduct the test whereas previously a “certified” installer or their company could do it.
The Duct Leakage Test:
Duct leakage measurements are used to diagnose and demonstrate leakage & efficiency problems with the system, and certify the quality of the installation. These tests are based off the CFA which is known as the Conditioned Floor Area. In all cases we seal up all the registers and then hook up a calibrated fan (as seen above) and pressurize the duct system to 25 Pascals (Pa). This number is then divided by the CFA which gives us a percentage.
For example; using a common layout – you have 2 systems in a 3000 SF house (not including the garage.) It is a 2 story with a basement (& to make life easy each floor is 1000 SF in size) you would only have to test the 2nd floor system as it is probably located in the attic or at least some of the ducts are.
Congratulations your HVAC installer did a good job and you only have 50 CFM of air leakage. 50 into a 1000 gives you 5% leakage. Unfortunately while that maybe a good number it still fails the “prescriptive” path which requires 4% or less. Depending on when you tested you might be able to remedy that or you might have to go to more extreme measures.
What types of testing can I do & when?
While there are four common tests (for residential & some small commercial situations), only three are recognized under the EEB Act. Depending on test determines when you can do it.
- The “Total Duct Leakage” or “Post-Construction” test is done after all the finishes are completed – house is painted, vent covers are on, etc… and we cover over the registers themselves
- The “Rough-In Test” is done when the system is fully installed (minus register covers) but before the drywall goes up. In this case we simply seal up the vent openings. The best thing about this test, is it allows you to make needed corrections before the finishes are installed and is the most popular option.
- If the air-handler is not installed, a “Rough-In” test maybe still be completed but you are only allowed 3 CFM per 100 SF as compared to 4 CFM for the other two. Please note all the ducts must be in place including the ones that “bolt onto” the air handler.
- The “Leakage to Outdoors Test” is not acceptable for code compliance but rather is a specialty test required by certain programs like ENERGY STAR and must be done “Post-Construction.” This requires pressurizing the house (using a blower door) & duct system (see above) to 25 Pa & measuring how much CFM of air is required to bring the system up to 25 Pa.
Cost’s (in local service area):
Single Package System……………………………………………………….…….$250
Additional Systems…………………………………………………………….$150 each
Supply & Return Registers over 10′ up (need notification)………..Please Call
Combined DET Verification (W/ 1 HVAC system)…………….$400 (save $100)
Leakage to Outside Test (need notification)………………………………$400
Combined DET Verification (W/ LTO)………………………………………$475
**On Site Training, Consulting, Diagnostic Time………………………$125 hr.
Rush / Emergency Charge (aka same day charge)……..……………Please Call
System Retest……………………………………………………Same charges as Above
Negotiated Contract Pricing is available for sub-divisions and multi-family projects depending on size & amount of units to be tested.
Additional Info: Duct Testing 101 — Dust Testing FAQ’s for Homeowner’s — Common Duct Leakage Area’s & Methods (aka how to pass the first time (Note: specific area’s and methods start 1/2 way down)