What Should You Do with the Ductboard found in your HVAC system?

Ductboard

Last Thursday & Friday, Mike W. employed the Bird Pros to redesign his duct system. Part of the problem with his discomfort was that his duct system contained a lot of duct board.

Do you feel like your indoor air quality is suffering? Take a look at your HVAC unit. Do you have plenums (large boxes with ducts attached) made from fiberglass duct board?

It's entirely possible that the construction of your air distribution system is a major source of your discomfort!

Take a look at my picture. It's Mike's duct board we replaced in his HVAC system. The interior surface is unfinished fiberglass. Those tiny, microscopic glass strands can break off and enter the airflow.

There's no filter to catch these fibers on the "SUPPLY side" of your HVAC system. Consequently, these glass strands can be carried with the airflow, into your living space.

Careless duct cleaning techs can also damage the inside of these boxes, and there is the risk of more strands being released.

Some remedies:

  1. Do It Yourself: paint the inside of the duct board with latex mastic. Use a paintbrush. You'll have to remove the ducts from the collars, to gain access. Hopefully you can reach everywhere without needing to remove the plenums. It's messy work!
  2. Replace (redesign) the duct board with sheet metal. You need a pro for this. If you're going this far, perform a Flowhood test, to determine where & how much improved airflow can be had. Odds are, the efficiency/airflow of your duct system can be [greatly] improved!
  3. Coat & Seal the interior of the duct board, using an airless sprayer. Consider using a pro for this job.

I've seen homeowners use filter media (1" thick, trim with scissors), and place behind each SUPPLY grill. Please, Please DON'T DO THIS! This dramatically restricts airflow through your system, especially when a layer of dust & hair covers the filter.

Many homeowners coexist peacefully with their duct board. If you're one of those, count yourself fortunate and blessed indeed.

Identifying if you have duct board is something to consider if you're concerned about respiratory issues and the indoor air quality of your home.

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