Duct Sealing


Out of sight, out of mind, right? This old axiom applies to most aspects of an air conditioning system and especially to the duct system. If you are like most homeowners, as long as your system is keeping you comfortable, you don't usually give it much thought. But what you don't see could be costing you a lot of money each year. Most duct systems are installed in attics or crawlspaces/basements where they are rarely seen or inspected. Our experience tells us that most HVAC systems have been poorly sealed when installed, and fittings may have come loose, and duct runs may have become disconnected. All of this leads to a lot of lost air – air that costs you dearly in the pocket

Through cracks and poorly fitting or loose duct connections, heated or cooled air is lost to your attic, crawlspace, or basement. In addition to increasing your utility bills, excessive duct leakage may expose you to indoor air quality problems.

Your HVAC system continually recirculates air throughout your home. Leaks in the duct system can draw air from surrounding areas such as attics, garages and storage areas. As a result of this leakage, dust, carbon monoxide from your garaged automobile, pollen, and other contaminants can be drawn directly into your system and distributed through your home.

Just by virtue of the way a duct system is built, it will leak at a rate of 10-12%. With new building codes in place, a sealed duct system must not leak more than 6%. As the house gets older though, these leakage rates increase with expansion and contraction of the system as well as with parts that break down with time. It is not uncommon for us to see a 15-20 year old system leak in the 30-50% range. That means that 30-50% of the air generated by your system is not getting to the areas of the home it needs to, leading to higher energy bills and low indoor air quality.

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The Home Energy Solution:

Depending whether your home has flexible duct or old metal rectangular duct, we have the solution for your needs. Our object is to make your duct system work the way it was originally intended to by redirecting the air generated from your heating and cooling system to the areas of the home where they are needed and, in turn, alleviate the air leaking into your attic, crawlspace, or basement. The result lies with much lower energy bills, a balanced air distribution throughout the home, and a higher level of indoor air quality.

As with air sealing, reducing the overall leakage in your ducts carries a very rapid payback on your investment. If your ducts are severely leaky, sealing them will offer an even higher payback than air sealing, and the return on your investment could be within 6 months to a year maximum.

Properly sealing ductwork results in several benefits. It improves comfort by increasing the rate at which air is delivered to a space; it can prevent safety problems caused by carbon monoxide gas leaking from water and space heating equipment; and it improves indoor air quality by reducing the infiltration of dust, humidity, and outdoor fumes and odors. Depending on your home's rate of leakage, proper sealing of these ducts can save you exponentially on your heating and cooling bills. It is also a project that carries with it one of the quickest rates of return of all energy efficiency upgrades.

Areas We Seal with Permanent Mastic Sealant:

  • All Registers and Boots leading to the subfloor
  • All Metal Duct Seams on Branch Runs
  • A-Collars (Point Where Duct Connects to Trunk Line)
  • Seams in Air Handler, Trunk Lines, and Junction Boxes


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See Benefits of Duct Sealing