Duct board or fiberglass-lined ducts versus metal ducts?
primitivelamps
| Posted in GBA Pro Help on
I have never liked duct board or ducts lined with fiberglass. The idea of the porous insulation on the interior just doesn’t seem like a good idea. The porous surface seems like it would affect air flow ( I understand properly sized this shouldn’t be a problem), collect more dirt than metal, delaminate and come apart over time, and are very hard to clean once dirty.
Just wondering on everyone’s opinion on ductboard and fiberglass insulation installed inside the ducts. I can’t seem to locate many good study’s relating to duct board verse metal ducts.
Thanks.
Terry
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Replies
Terry,
You're right that galvanized metal ducts are generally the highest quality ducts. Of course, they still need to be wrapped with duct insulation.
Here in the Northeast, galvanized ductwork is standard -- we don't see much ductboard or flexible ductwork.
Terry,
I understand the fiberglass insulation on the inside is for noise reduction. I agree this sounds like a really bad idea, but the HVAC guys state people would never accept the noise level if they didn't line the ducts. Does anyone out there know of a better way?
galvanized duct with better soundproofing on the outside perhaps? The bonded logic cotton batts are good for something, at least in their 2" R8 roll format. I wrapped 6" and 8" newly installed galv. duct so they exceed code for insulation and the material is better than fiberglass for sound transmission. So far so good. Admittedly, doesn't install as easily an fiberglass but performs better in this application.