Replies

1. GBA Editor
   Martin Holladay | Apr 28, 2016 04:50am | #1

   Eric,
   PVC has an odor, especially when it is hot. I haven't read any studies of PVC offgassing, however.

   Green builders avoid using PVC pipes as supply air ducts.

   Your question is confusing, because your title refers to "ventilation returns," while the body of your question refers to "supply air." Most HVAC documents distinguish between supply air and return air, but you seem to be confusing these two systems.

   When referring to HRVs or ERVs, we usually speak of fresh air ducts (also called supply air ducts). These can be galvanized or polyethylene -- but I wouldn't use PVC. The exhaust ducts (the ducts that pull air from your bathroom and send it out of the the house) can be PVC if you want.

2. 
   mikkelsen | Apr 28, 2016 11:41am | #2

   Thanks Martin, yes, my verbage was off. I was referring to the supply or fresh air ducts, and wondering why PVC isn't recommended for these, especially if they're not being exposed to hot air. Thanks for helping me get the lingo correct.

3. 
   mikkelsen | Apr 28, 2016 11:50am | #3

   What about ABS pipe?

4. GBA Editor
   Martin Holladay | Apr 28, 2016 11:52am | #4

   Eric,
   I wouldn't use ABS either -- but it's your house. Any reason that you don't like galvanized or polyethylene ducts?

5. 
   mikkelsen | Apr 28, 2016 12:04pm | #5

   I think the plastic pipe is just easier to work with and seal. Is there any readily available polyethylene pipe and fittings that are cost comparable and easy to glue/seal?

6. GBA Editor
   Martin Holladay | Apr 28, 2016 12:18pm | #6

   Eric,
   The only polyethylene ducts I know of are manufactured by Zehnder, and they're not cheap.

7. 
   mikkelsen | Apr 28, 2016 01:12pm | #7

   yeah, thanks Mantin