1

Planning to install an ERV (Energy Recovery Unit) and have been advised that a concentric vent is easier to install and the risk of short circuiting output and input is negligible. My feeling is if I am willing to invest to install an ERV, it might as well be done optimally. Is it significantly better to install two vents, one input, one output, and space them appropriately (say 6”), or is a concentric vent “good enough”?

I feel the air in my house is rather stale.

Thank you!

isherwood
  • 119,766
  • 7
  • 148
  • 349
user1114802
  • 13
  • 2
  • How is the ERV you are planning on buying set up? I would imagine that if it's designed for a concentric vent, you're going to have a hard time making it work with separately plumbed vents, and vice versa. – FreeMan Sep 24 '21 at 14:22
  • Four port ERV with the option of buying a concentric kit to merge the input air and exhaust air into the concentric vent. – user1114802 Sep 24 '21 at 17:25

1 Answers1

2

Firstly, I agree the the incidence of recirculation is likely negligible, assuming you terminate in an open area. Combustion appliances use concentrics by the millions without problems. If you jam it in a corner you could have problems, of course.

Then, a 6" spacing doesn't do anything that a concentric termination doesn't already do. You'd need to space them apart several feet or more to (almost) completely eliminate recirculation concerns.

Finally, a small amount of recirculation is not dangerous. It merely reduces overall efficiency slightly. Whether that minimal concern is worth the hassle of running separate ducts is up to you and local conditions.

Disclosure: I'm not an HVAC tech, nor am I certified in any way to give advice. My knowledge is based on long experience and association with experts.

isherwood
  • 119,766
  • 7
  • 148
  • 349
  • What's with the disclosure? I think it's understood this is all experienced DIY or professional internet advice here, caveat emptor. Those who wish to declare their credentials or lack thereof could do that much better in their profile. No? – P2000 Sep 24 '21 at 17:19
  • there are user profiles to check, @P2000? ;) many people don't bother. Some people post their location in their profile, yet we ask for that all the time. BTW- my profile wouldn't give any of my answer any credibility. (there goes all future up votes.) – FreeMan Sep 24 '21 at 17:35
  • I'm more likely to make the point when discussing HVAC and other potentially health-related things. Maybe it was just a mood. I dunno. – isherwood Sep 24 '21 at 18:00