Duct Test

A duct test helps builders comply with Utah energy code.

Efficiency in a residential home’s duct system ensures that the correct amount of heated or cooled air is delivered to the correct space. This ultimately saves hundreds of dollars annually for homeowners now and in the years to come. Some reports suggest that an leaky duct system can account for as much as 25-30% of a homeowner’s energy bill year-to-year. Think about all that conditioned air being pushed into an unconditioned attic.

The Duct Blaster Test quickly and efficiently identifies how much air leaks from inside the duct system. We use a combination of blocked registers, sensors and pressurized measurements to gather data about the tightness of the home’s duct system. In the event of system leaks, we employ theatrical smoke to visually see where leaks exist.

Duct Testing Building Science West

Why Build With Air Tightness In Mind?

Meet Building Code

Cash In On Energy Rebates

Build a Superior Product

Leave a Smaller Energy Footprint

Reduce Long-Term Energy Costs

Avoid Interior Moisture Condensation

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How Does the Duct Test Work?

  1. A technician will mount a duct blaster onto your return air handler. The remaining supply and return ducts will be sealed air tight.
  2. The duct testing unit includes a computer with brass inputs and pressure sensors. One of the sensors is measuring the pressure inside the home, and the other sensor is measuring air pressure on the inside of the HVAC system. We measure industry standard pressure differential in the duct system using a measurement of 25 pascals.
  3. The duct testing machine includes a smart fan. This fan knows how much air is moving through it. There are tubes in the middle that sense the air. The sensors gather the pressure differential.
  4. The pressure difference simulates a HVAC system operation acting on your duct system.
  5. The duct blaster pressurizes the HVAC system and then identifies how much air leaks.

Utah Code

Duct Test

Utah code states that to pass the air tightness and insulation installation, air leakage must be less than seven CFM per 100 sq ft of conditioned floor area (commonly referred to as 7%) @25Pa. Older homes will see a higher score because of older materials, and leaks caused from wear and tear.

The test is pass/fail. When you pass, you can receive a certificate of compliance and homeowners can move in. If the house fails, efforts will need to be made to seal the duct system before a retest can occur.

Cost of a Duct Test


Prices vary depending on the size of the property, number of homes needing tests and if you are combining multiple services. Please call for a quote.

The cost includes the time to duct test your property, production of the required reports, submitting all of the required paperwork for your rebates, and following up with your office to make sure you received the payments. When combined with a Blower Test, or other Green Builder Services, you can receive a bundle discount.

How to Adequately Seal the Duct System As You Build

  1. Seal each component as completely as possible before it is attached to the system
  2. Seal each new attached piece of ductwork as it is attached to ensure as much of the seams as possible as sealed
  3. Use duct mastic where ever it is appropriate. Duct mastic does a better job that foil tape (even UL listed) for most duct sealing
  4. Mastic registers to the subfloor
  5. Seal the inner AND outer portion of flex duct with mastic and zip ties
Building Science West

Stop running around trying to figure out how to manage energy efficiency tests on your own. Forget about doing the paperwork, and printing reports. Let us do the busy work; staying up on code, compiling reports, filling out paperwork. After your duct test is complete we will submit your rebate paperwork. Call our office today.

Duct Testing in Ceiling

Where Do Duct Systems Most Commonly Leak?

  • Site built joints between duct components
  • Gored (adjustable) 90-degree elbows (leak at the gores or slip joints)
  • Factory seams in galvanized sheet metal ducts
  • Flex duct to spider box connections

Signs There Are Leaks in Your Duct System

  • Inconsistent temperature throughout house
  • Outdoor smells and odors being brought inside
  • Odor from appliance outputs, such as a dryer, smelled inside
  • High energy bills
  • Excessive dust
Duct Testing


  • Inadequate sealing of joints where the duct system components connect
  • Constant expanding and contracting during hot and cold seasons can wear and tear on an HVAC system
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