My aged in-laws have obvious damage to 20-year old flexible forced air ducts in their attic. Rat droppings and tunnels throught the blown-in fiberglass insulation suggest that rats may have been chewing on the ducts.
A 25-foot section of duct is split on top for nearly the whole run. gray plastic outer skin is peeled away, plastic mesh is split as well, and the insulation blanket is falling away from the inner wire-reinforced air duct. I can feel air leaking from bwetween the insulation layer and inner labor. Other similar ducts look undamaged.
HVAC company tells my in-laws to replace all ducts because “the rest of them will split soon anyway”.
Do flex ducts really split simply due to age, as he says, or is he just trying to increase the value of the job?
Thanks,
BruceT
Replies
If rodents have access to the ducting it should be replaced whether it's split or not; if they've penetrated the outer skin, they've most certainly entered the interior of the ducting and built nests and spread their droppings, dead offspring, urine, dog food....if they're packrats they may have even packed some of your in-laws belongings up there. (I'm serious).
In addition to reducing, or even totally blocking the ducting, there is a health hazard that is spread throughout the house whenever the blower cycles on. And, depending on the type of furnace and the distribution of contamination, there may even be a fire hazard.
Ducting throughout the house should be cleaned or replaced if possible (there is, by now, likely an accumulation of stuff in ducting other than the attic and in the the plenum). Areas accessable to critters should be replaced with metal, or at least run with duct board and encased in a chase or soffet.
I've not seen the longitudinal splitting you describe, but I've seen the rodent problem.
Flexible ducting is economical and easy for the installer, but is not always very efficient unless unstalled very carefully.
Installing metal ducting is not beyond the ability of a DIYer, especially if it just involves replacing existing runs....if cost is an issue, maybe you can volunteer.... :-)