Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

Concentric venting for a 96%er.

STEVEusaPASTEVEusaPA Member Posts: 4,143
Hello gas gurus. Stepping outside my knowledge with venting for a 96% gas furnace (for one of my investment properties I'm rehabbing and having a relative live in).

My only option is to go thru the roof (existing chimney). There's no option to get it from the middle of the house to an acceptable/approved outside wall.
I have a chimney that has to either be rebuilt (not likely) or I planned to take it down below the the roof line, probably to the ceiling joists. 6" terra cotta lined.

I'm familiar with concentric vents at the roof-run exhaust/intake up to attic separately, then into the roof kit.
What I was wondering was can I (do they make?) a concentric that I can run down the chimney using it as a chase) to the mechanical room (total run <25 feet), then split out my exhaust and intake in the mechanical room? Both pipes wont fit into the chimney separately, and running a separate pipe up next to the chimney requires lots of demo.

Was looking at various furnace manufacturer's install kits. Although they show a concentric under the roof with the kit, I haven't seen one showing it running the entire length and splitting back out at the furnace.

Thanks for your input!


Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!