Ducting Systems and Air Ventilation - What is this insulation stuff inside the vents??

I'm having my heat pump replaced, and some of the ductwork is insulated on the inside. The insulation is about an inch thick, kinda looks like the fiberglass in the walls, black on the inside surface, and holds dust like crazy. It's retained by what appears to be studs welded to the walls of the duct with 1" diameter washers, and reddish glue sticking it to the duct. The round ducts are insulated on the outside and fairly clean inside, but the square ones have this dust magnet nasty stuff. Is this normal?
thanx

Pretty common stuff depending on the age and your location. And yeah, what you see is normal.

As I understand, a better option is the metal duct with the insulation on the outside. Don't know why its on the inside, maybe an HVAC Pro will explain.

I'm real tempted to get a quote from the sheetmetal shop, or price some ductboard.

So you will be going from lined duct to duct board! That makes no scene. Duct board is fiberglass to.

So you will be going from lined duct to duct board! That makes no scene. Duct board is fiberglass to.

That's why I'm asking stoopit questions, cause I've no clue (obviously)!:confused:

Why not get what you have cleaned, then you can put a coating on it like Foster 40-20.

Why not get what you have cleaned, then you can put a coating on it like Foster 40-20.
Should a brush attachment on a shopvac get enough of the dust off to use the 20-40?
That insulation just seems like a real dust trap when I saw it for the first time, but I guess after 20 years, it isn't all that bad. It's just hard to put dirty stuff back on new equipment.

Being in the IAQ field I would say no way to the shop vac. You will be putting all that dust back into the home. If your main duct line is lined you will not be able to clean it with a shop vac. You will have to call a duct cleaning company to do it. If this is something you will think about ask us first there are a lot of bad duct cleaners out there.

Actually the only practical solution is to get rid of ductwork in its entirety. Go all electric, or install baseboard hot-water heating, or install those new ductless Mitsubishi heating/airconditioning combination units that mount on walls.

Ductwork is by far the nastiest, most dusty, unhealthy thing ever conceived by the human race. All kinds of unsavory things live in them -- dead roaches, lizards, etc. And they also collect moisture from condensation.

No matter what kind of filter is being used, the dust continues to circulate back and forth through the ducts and recycles through the whole house for your breathing pleasure.

The government would probably outlaw gaspacks and ductwork were they not fairly environmentally friendly, and reasonably affordable compared to other systems. :coffee:

Actually the only practical solution is to get rid of ductwork in its entirety. Go all electric, or install baseboard hot-water heating, or install those new ductless Mitsubishi heating/airconditioning combination units that mount on walls.

Ductwork is by far the nastiest, most dusty, unhealthy thing ever conceived by the human race. All kinds of unsavory things live in them -- dead roaches, lizards, etc. And they also collect moisture from condensation.

No matter what kind of filter is being used, the dust continues to circulate back and forth through the ducts and recycles through the whole house for your breathing pleasure.

The government would probably outlaw gaspacks and ductwork were they not fairly environmentally friendly, and reasonably affordable compared to other systems. :coffee:

How is going to a lot of ductless splits going to be better? Its not!! Have you torn down a unit before to get to the mold that is growing in them? It's a #^@& to get in to a lot of them.