Painting HVAC ducts ??

Old 11-07-17, 07:59 PM
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Painting HVAC ducts ??

Ok so here goes.
Im remodeling my basement, and I want to paint the ceiling and all the utilities that run through it.

My issue is that some ducts are wrapped with insulation.
Most of the supply square ducts are wrapped, not all though.
The square supply branches off to round ducts. Again, some are wrapped, some arent.
Its a small system in a 1500 sq/ft home. Gas burning 65 year old Lennox monster.

The ducts are in an unfinished basement. There sre no registers in the basement area.
Its not climate controlled. But..... It stays the same temp year round.

So how important is the insulation ? Id like to take it off to paint the metal ducts.
Really I'd only be removing 3 ten foot section. Leaving some insulation in place on ducts in areas
not to be painted.

Will I devastate any efficiency of this old system?
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Old 11-07-17, 08:44 PM
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Given the age of the system, my first concern would be about asbestos. It's hard to tell from a picture, but I had old ductwork that had white tape at the seams like that, and the tape did test positive for asbestos (though yours might not). I can't even begin to guess about the rest of the insulation.
Old 11-07-17, 10:03 PM
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Yep, that would be my concern as well.
I have seen the insulation painted.
Old 11-08-17, 11:11 AM
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Im afraid its asbestos too. But I will just paint over that.
The insulation was added many years after the system was built. Its just the regular ole fiber glass insulation.
I think my father put it on , an used packaging tape and speaker wire to install it all.
My main concern is loosing a lot of efficiency by removing some of the insulation. Its not really efficient to begin with.

Can I just pull off the insulation and paint the metal ?
Old 11-08-17, 12:08 PM
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It's been years since I've painted any asbestos wrap on duct work but it paints well. Metal ducts often have an oily film on them [even years later] and if it isn't cleaned off - latex paint won't bond well to the metal.
Old 11-08-17, 04:53 PM
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Painting the wrap will not change the heat transfer to the basement, but both painting and removing the wrap will increase that loss, ie less efficiency. Metal ducts are usually reflective and have low radiant heat loss and obviously removing the insulation will increase the loss.

However, if you insulate the basement walls most of that heat loss will remain inside your conditioned space, actually nice warm floors. Air seal and insulate the rim as well.

Old 11-10-17, 12:46 PM
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Ah , I didnt think of it that way. The heat "lost" will be enjoyed by folks hanging out in the basement.
I guess stealing a bit of heat from the upstairs dwellers.
I'm going to go for it.

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