© 12 November 2019

by Louisville Climate Action Network

CONTACT US

PO Box 4594

Louisville KY, 40204

502.451.COOL (2665)

Monday--Friday, 9am--6pm

FAQ

SOCIAL

DUCT SEALING

Send conditioned air where you want it, not where you don't.

Why Seal Your Ducts?

A great way to improve comfort and air quality is to ensure warm or cool air conditioned by your HVAC system is delivered where you need it.

Most Louisville homes and businesses have ducts with bad connections, leaks and kinks.  Some deficiencies occurred during fabrication or installation; others developed over time or were caused later by inattention or corner-cutting. 

 

Because duct problems can divert up to 20% of your HVAC output, it's smart to find and fix as many as you can. 

Locating Leaks

Some duct problems are readily accessible:  Lift vent registers and return grilles to see whether connections between ducts and floors/walls are sealed.  Look in attics and basements for leaky connections and kinked ducts.  Make sure vents and returns aren't blocked by furniture, boxes, etc.  Check for light coming into the filter frame.

Better, have ducts pressure tested by an energy auditor or your HVAC contractor; they have special equipment for quantifying and detecting leaks, even the ones created during fabrication or installation, and hidden between walls or floors.  

Courtesy of the USEPA.

Fixing Leaks

DIY Method One:  Aluminized Duct Tape

Clean the duct for about two inches all around any gaps you can find, then apply aluminized duct tape.  Press firmly to ensure good contact.

DIY Method Two:  Mastic

Using an inexpensive, 1-inch-wide paint brush, apply mastic compound across any leaks you can reach.  Wear old clothes and be careful, because --- once it's dried --- it's difficult to clean up and doesn't launder well.

Contractor Method One:

Ask your contractor to correct disconnected ducts, straighten any kinks and apply mastic compound over the leaks they can reach. 

Contractor Method Two:

Hire a contractor offering internal sealing, using a water-based polymer, such as Aeroseal.  This method is the fastest and most thorough, because it fills leaks even between walls and floors, too close to ceilings to access by hand, etc.