Should I seal or replace leaky return ducts?
Leaky ducts pull in dirty crawlspace air, clogging filters rapidly and causing extreme temperature differences between floors. HVAC contractors often give conflicting advice on whether you can effectively seal these hard-to-reach gaps with pipe wrap to save money, or if a full replacement is necessary.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Sealing gaps with mastic tape or spray foam
- 2Replacing registers with slightly bigger ones
- 3Cutting a piece of plywood to fit the area, screwing it down, and using spray foam
- 4starting a resealing and insulation project
- 5using insulated pipe wrap
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“I’m sucking up crawlspace air into the filter which is getting dirty extremely quickly.”source ↗
“I’ve had 2 HVAC companies out to look at it and I’m getting different advice on what to do.”source ↗
“I know the system is towards the end of its expected life but if I can kick the can down the road some I would like to save the $$$ right now.”source ↗
“I discovered this enormous gap in a supply hvac vent.”source ↗
“We have always noticed that the basement is much hotter than upstairs in the winter when heat is on; and much colder than upstairs in the summer when AC is on.”source ↗
“Is this something I can use insulated pipe wrap effectively or do I need to replace this duct . It is a very hard to reach area.”source ↗
Where this came up
People with this problem also raised
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- 7How to seal window gaps around an air conditioner against insects
- 4Can you service an HVAC system with leak seal in it?
- 12Why is my ductwork dripping condensation inside the walls?