Priority Energy, IECC Duct Testing, IL

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Duct Tightness Testing (IECC 2018)

Since 2009, under the IECC Code, ducts, air handlers and filter boxes shall be sealed, and joints and seams shall comply with either the International Mechanical Code or 2018 International Residential Code. Unless 100% of all ductwork is located within conditioned space (see definition below), a Duct Tightness Test must be performed to verify compliance. This means that any time you run a duct outside the building envelope (in the attic, crawlspace, or garage, for example), the entire system must be tested. 

Priority Energy has experienced BPI-certified Duct Test technicians who will conduct the test and provide a signed, written report for your Village Code Official. 

 It is not an easy test to pass.
Click here to see Duct Test results from across the Chicagoland area.

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

Ducts shall be pressure tested to determine air leakage by one of the following methods (IECC Section 403.3)

A Rough-In Duct Test

If this test is performed before the air handler or registers are installed (typically before drywall), the requirement per IECC 2018 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. 

If the duct test is performed after the air handler has been installed the IECC 2018 allowable leakage is 4 CFM of leakage per 100 sq.ft. of conditioned floor area.

At the rough stage of construction most well-sealed systems Pass, or if they don't Pass it is still possible to locate the leakage points, seal them and perform a re-test.

For example: If you have an HVAC system serving the second floor of a house with 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 system. This is not a lot when you factor in all the connections in a typical duct system (take offs, elbows, boots, cleats, etc.). 

A Post-Construction Duct Test

Priority Energy does not recommend waiting until completion of the home to perform a duct leak test as it becomes much more difficult to attain the minimum air leakage requirement once the air handler and register covers have been installed. 

We understand that sometimes the duct test is missed and needs to be done later in the construction process or after completion. Priority Energy can help, but our technicians want you to know that it is not uncommon for most systems to Fail once a home gets further along in the construction process. 

A finished home is allowed 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 acceptable leakage (56 CFM from our previous 1,400 sq. ft. second floor example), and should be easier, it is not. Factors such as the ductwork being concealed by drywall and insulation, an installed air handler (which can leak as much as 100 – 200 CFM on its own), and registers being in place combine to make a much leakier and harder to seal internal system. To test at this stage means we have to tape over these areas and also test the connections between the boot and subfloor/drywall, which is not ideal.

If your Ductwork Fails the Duct Test

Our technicians evaluate duct systems every day and can help you locate the leakage points in your system with our diagnostic equipment. (There is an additional charge for this service.) We will provide you with as much guidance as possible, but depending on where the leaks are located and how much leakage is occurring, your best and only option may be to use Aeroseal, the aerosolized, non-destructive duct sealing process. 

Priority Energy is an authorized Aeroseal provider to the Chicago area.

Ductwork in Conditioned Space*

For ducts to be considered as inside a conditioned space (IECC Section 403.3.7), such ducts shall comply with either of the following:

  1. The duct system shall be located completely within the continuos air barrier and within the thermal envelope.
  2. The ducts shall be buried within ceiling insulation in accordance with Section R403.3.6 and all of the following conditions shall exist:
    -  The air handler is located completely within the continuous air barrier and within the building thermal envelope.
    The duct leakage, as measured either by a rough-in test of the ducts or a post-construction total system leakage test to outside the building thermal envelope in accordance with Section R403.3.4, is less than or equal to 1.5 cubic feet per minute per 100 square feet of conditioned floor area served by the duct system.
    The ceiling insulation R-value installed against and above the insulated duct is greater than or equal to the proposed ceiling insulation R-value, less the R-value of the insulation on the duct.

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

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    Anonymous Builder
  • We were so impressed with the amount of information the Priority Energy technicians gave us during our ENERGY AUDIT.  If you are buying a house, I would strongly recommend having them do an energy audit on it, in addition to your usual home inspection.

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    A.S. Architect
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    BPI Student, L.E.
  • There is much less dust in the house and the monthly gas and electric charges have been reduced by 10 to 15%.....I'm sure I will see greater savings over a twelve month period......thanks again.

    Aeroseal Client, R.N.
  • Just completed my BPI Field exam for my Quality Control Inspector (QCI) certification renewal at Priority Energy.
    Such a convenient and well-set-up training and test center with caring and knowledgeable staff and proctors! Thanks folks!


    P.R., Ottawa, IL
  • It's been cold here for the past few days and I really feel the difference in heating since the building was Aerosealed! My apartment is so much warmer now. Thank you Priority Energy!


    Miruna; Tenant at Country Manor Apartments, Peru, IL
  • Anytime I can be a reference for all the great work on my (new) house, please let me know.  Priority Energy is outstanding at what they do!

    Executive at Medline Industries, IL
  • I have a two story home built in the mid seventies. Lots of temperature fluctuation between the floors. The Aeroseal process dramatically increased the air flow to the second floor. Good experience. The company was very informative, answered a lot of questions.

    Vince from Oakbrook, IL
  • "It's been cold here for the past few days and I really feel the difference in heating since the Aeroseal, my apartment is so much warmer now. Thank you!"  

    MP from Peru, IL
  • Thank You so much for the super-fast turn around of our Manual J, D and S reprt for the Village of Glen Ellyn. Our original Manual J kept getting kicked back to us for corrections but your calculations/report got approved instantly-no questions asked and no more permit delays!

    Kim, Glen Ellyn, IL
  • Thank you. Truly. I appreciate you taking the time to clarify things for me and then going above and beyond to ensure that my CEUs are handled for our current RESNET cycle. You’ve always been kind to me and this is another shining example of that.

    Craig, HERS Rater, Batavia, IL
  • (Aeroseal) is a GREAT Product! Really made our townhouse more comfortable!

    Gordon; Chicago, IL
  • We are having less ice on roof since the Aeroseal duct sealing! Thanks!

    Bill; Downers Grove, IL
  • Duct sealing (with Aeroseal) was the smartest thing I ever did! Our home is sooooo much more comfortable! We were so very pleased with Priority Energy and their technicians!

    Richard; Lake Forest, IL
  • On to the Radon issue - Excellent results with Aeroseal!  From 5 + to a .4.  Before sealing like we discussed, I had warm air coming out of the sump basket with the furnace running. Even with the furnace running, it is still pulling air in now.

    Bill; Belvidere, IL
  • Pat was awesome and super helpful! We are experiencing weak air flow in the duct system of our 1950''s home and Pat gave us great recommendations to fix the problem when we do our remodel.

    David; Arlington Heights, IL
  • Already the house seems more balanced (since Aeroseal duct sealing yesterday) .. far end of house is getting more warm air flow!

    Bryan, November 2019, Chicago, IL
  • Priority Energy did a great job with an Aeroseal project for my home. The rooms are more comfortable and even throughout the house, including the far registers which never used to get significant airflow. Very honest and trustworthy

    Bryan, December 2019, Chicago, IL
  • I hired Priority to seal the ducts and air seal my home.  I have been very pleased with

    the results.  The personnel from this company are professional and quite competent.  I have literally saved

    Nelson, Lake Forest
  • Priority Energy did a great job with an Aeroseal project for my home. The rooms are more comfortable and even throughout the house, including the far registers which never used to get significant airflow.

    B. L., Chicago, IL Feb. 2020
  • Used Priority Energy to help insulate (Aeroseal) a property we purchased and could not have been happier.
    R. M., Lake Bluff, IL April 2020
  • Very knowledgeable and professional (Aeroseal) staff. I definitely highly recommend and would use again in the future for other services!

    D.F., Chicago, IL Feb. 2020
  • Employees were all very helpful and professional! Came out in a timely manner (to do our Duct Test). Would highly recommend this company!

    J. R. New Lenox, IL April 2020
  • I had Priority Energy analyze my older home for indoor air quality and comfort because I was having difficulty maintaining temperatures. They came out and discussed our options. We ended up sealing our ducts and installing a whole-house dehumidifier.

    D. L, Lake Zurich, IL Feb. 2019
  • Priority Energy did an aeroseal for our home. We have had issues with air flow in our kitchen (cold in the winter) and one bedroom upstairs (hot in the summer). After they were complete, there is such a stronger air flow from the vents, that it really makes a difference.

    J.J. Chicago, IL - November 2020
  • Excellent Service and Company to work with - highly recommended and professional!

    T. B. Chicago, IL - July 2020
  • Before we sealed our ductwork the rooms farthest from the furnace were always hotter or colder than the rest of the house. We felt an improvement in air flow to the kids rooms right away. 98% duct leak reduction!

    S. H. Glenview, IL - October 2020
  • The Energy Audit you did on last home was so helpful; we referred to it for years when we made home improvements. I'd like to have you do an audit on my new home now. B. A.

    B. A. Lake Forest Homeowner
  • "We were impressed with how well your technicians answered our questions and how quickly and neatly they performed our Aeroseal service. Our rooms are much warmer now that the duct leaks have been sealed! You have a great team."

    D.F. Palatine, IL
  • "You have a great Aeroseal team. We were impressed with how well they answered our questions and how quickly and neatly they performed our service. Our rooms are much warmer now that the duct leaks have been sealed!"  

    D.F., Homeowner in Palatine, IL
  • "We enjoyed meeting Dave, our Energy Auditor.  He was interesting, knowledgeable, and professional.  We appreciated all his time and effort." 

    S.B., Homeowner in Prospect Heights, IL
  • Priority Energy is an A+ company! I've been having issues with my house staying warm in the winter so I called them up and they came out right away. Kurt was so helpful and professional! He explained everything that was going on in my house and gave me  peace of mind.

    M.I., Homeowner in Norridge, IL
  • "The employees that showed up were friendly and took care to make sure they kept the house clean while performing the aeroseal job. They explained the procedure thoroughly, I would recommend this company A+."

    T.B., Elgin, IL
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    R.N., Inverness, IL
  • "I had Priority energy clean and then aeroseal my supply ducts; what a great experience! Great communication, great technicians, and great overall customer service!

    M.G., Downers Grove, IL
  • The Duct Leakage assessment we had yesterday was extremely informative! I'm glad we had you come to our home.

    D.K. Homeowner, Chicago, IL
  • Anthony was brilliant and answered all my questions. Really appreciate his expertise on our energy audit!
    January 2023

    S.K., Chicago, IL
  • David was very professional, thorough, and easy to work with. He provided us with a clear, detailed report with helpful suggestions as to how to improve our home.

    C.S. Chicago, IL
  • I highly trust and recommend this company for their prompt response, punctuality, and honesty in the performance of their service.

    C. H. Chicago, IL

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