[skline2]

We had some folks come out and do duct sealing for us. They were able to seal the supply ducts, but were unable to get the return ducts to seal. To do so would have required getting into walls, etc. We were told that it isn't a big deal. Sealing the supply side is most important. I would be curious to get the unbiased opinion of others if this is an issue.

 

[stick\shift]

Sealing the supply ducts is more important. The problem with leaky returns is they draw from least resistance, which could be closer to the furnace when you want it to be drawing from distant rooms.

 

[SeniorSitizen]

Depending on the filtering arrangement, leaking returns can supply dirty air to your unit. Our set-up is a good example of not wanting any leaking return.

 

[beenthere]

Aeroseal probably would have been the way to go.

https://aeroseal.com/

 

[skline2]

Aeroseal is actually what we used

 

[beenthere]

Aeroseal is actually what we used

Wow, must be some large leaks for it not to be able to seal the return.