test revealed insualtion(glass) particles in air

[chris311]

So I have been battling air quality issues since moving in. Working on getting humidity under control. I had air samples taken to look for mold which I had but it also nonoted that there was significant insualtuon particles in the air of all three levels. I have all metal supplies and returns and all are insulated. I am thinking perhaps there is a break in the line somewhere. My allergies are way worse when the AC is running. I'm trying to figure out where to start looking. If the supplies had leaks wouldn't air push out instead of bringing insulation into the airflow? If it was a return woukdnt the air filter catch most of that? Just trying to figure out the best way to handle this since most of the supples are above a sheetrock ceiling. Thanks for any input.

[unc99]

If you think that this problem is the result of the HVAC, you should probably have an HVAC pro come out and inspect the system. But here a few thoughts that come to mind about things that could generally cause this issue:

1. If you have an older home, the plenums and/or duct work may be made of fiberglass duct board. If the duct board has been damaged or is just deteroriating from age, this could cause your issue. I don't think this stuff is used much anymore for this reason. If your home is newer, your ductwork is probably a combination of steel ducts/plenum and/or flex duct, which shouldnt cause this issue.

2. Even newer systems will typically have fiberglass insulation in the air handler/blower compartment and around the coils. You could have an HVAC pro make sure this insulation is not damaged or deterioating which could cause the particles to be released in the duct work.

3. Is your furnace filter in filters grilles at the return register or right in front of the blower? If the former, then you could have a leaky return duct that is pulling in fiberglass insulation after the air has already been filtered, particularly if your ductwork is in an attic with insulation. If the latter, the filter at the blower entry should be helpful in catching any particles which enter the return ductwork, presuming it is high quality filter (ie, high merv rating). It seems to me that filters at the blower entry are superior for this reason, but are also harder for the average homeowner to monitor/change. Regardless of where the filter is located, consider upgrading it to a higher quality filter if you are considered about particulate in the air.

4. If you have ceiling return registers, make sure the return box is sealed to the ceiling to avoid having attic air pulled into the return side of the system.

5. I agree with your thought that it is unlikely this stuff is entering on the supply side, but obviously a leaky supply side is still a problem for other reasons. Although if you have ceiling supply vents you have an HVAC pro make sure the supply vent boots are sealed to the ceiling. If this wasn't sealed it could allow insulation into the air space if you have fiberglass insulation in the attic.

Good luck

[HotMama]

I would look into supply air duct leakage. Supply duct leakage causes your home to go into negative pressure. Let's say you have a 3 ton unit moving 1200 cfm, but 200 cfm of that is leaking into the attic. Your return is still wanting to pull 1200 cfm even though only 1000 cfm is being supplied into conditioned space. Now your home has to make up the other 200 cfm. It does this by pulling air wherever it can: around can lights, electrical outlets... This could be where the insulation is coming from. Not from the ductwork insulation but your home's insulation. It could also be why your humidity is out of control. If the ductwork is inaccessible to hand seal, look into Aeroseal.