What is the best product to seal HVAC ducts with?

Published by Lily Milani on September 22, 2010 - 12:08pm

My HVAC contractor has told me that he wants to use mastic to seal the HVAC vents. I am familiar with using aluminum duct tape but never heard of mastic being used. Also, is using mastic easier than apply aluminum tape? Thanks for your help

Most HVAC contractors will tell you that HVAC duct mastic is the best. It's fairly easy to apply and the most reliable. Sealing the ducts has to be done during installation of the system generally, because once the duct work is in, it is very difficult to get back into those tight spaces. Other HVAC contractors will use aluminum duct tape and this is acceptable as well. Make sure though that you don't use the ordinary duct tape that you buy at the hardware store or home improvement stores.

There an excellent overview about Sealing HVAC Ducts by Energy Designed Homes at http://www.energydesignedhomes.com/Papers/DuctSealing.pdf