Seal Leaky Air Ducts from the Inside

Sealing ducts from the inside has been around awhile, is it time to take the process serious?

by Preston

Duct Sealing From the Inside

Start-up Aeroseal has been getting decent media exposure lately with a writeup on Energy.gov and a listing on This Old House‘s Top 100 Best New Home Products of 2011. The company has an exclusive license to technology originally developed within the Indoor Environment Program at the Energy Department’s Lawrence Berkeley National Laboratory.

In short, Aeroseal sends a sealing mist through air ducts to eliminate holes and cracks of up to 5/8th of an inch — resulting in improved comfort and energy savings.

The potential for Aeroseal is enormous because a typical home with forced-air heating or cooling will lose about 20% or more of the air through leaks, holes, and poorly connected ducts, according to the U.S. EPA.

Aeroseal calculates that they can save Americans an estimated $5 billion a year on heating and cooling costs with their mist that is pumped throughout the inside of a home’s duct work.

Here’s what a qualified Aeroseal technician will do with Aeroseal:

  1. Test the ducts to get a baseline of leakage
  2. Block registers with foam or plastic
  3. Inject the aerosol-based mist into the duct system
  4. Run the system to seal cracks and leaks
  5. Monitor an attached computer/sensors for progress
  6. Test the ducts to measure improved performance

Of note, the sealant only binds to leaks without coating the rest of the interior duct, according to Aeroseal. The sealant is made with two main ingredients, vinyl acetate polymer (VAP) and 2-ethyl-1 hexanol (2E1H), and usually works without cleaning the air ducts.

The process takes anywhere from about four to eight hours, after which the owner is supposed to have improved air flow, more even temperatures, and increased energy efficiency. Aeroseal indicates that the sealing reduces duct leakage by up to 90%, or even more in some homes, and reduces energy use by up to 30%.

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original article at,  jetsongreen.com