Duct Insulation

This week we take a look at the various duct insulation material. The most common in use of course is fiberglass. This is the least expensive so far but has the obvious drawbacks. Most of us recognize the 1" thick wrap that looks like batt insulation but thinner, or the foil backed 1" thick wrap. These have good insulating properties but the obvious discomfort and health issues with installing them. The rectangular ducting in most small and large commercial applications has duct liner on the inside of the duct. For the first couple of years after a system is installed the liner remains intact after the initial blowout of fibers upon start up. However the fiberglass does deteriorate over time and fibers start to come loose. Yes on the supply side we are breathing this. On the return air side if it is pre-filter it can be captured. This does cause a problem when dealing with IAQ issues and the VOC's in the indoor environment. There is a common practice over the last 10 years or so to have schools and hospitals with exterior wrap insulation, done by professional insulators. This has worked out very well. However in the small commercial and residential market it has not been cost effective to this point. There are alternatives and we will look at some of those next time.