jinbtown t1_j6gv0l7 wrote on January 30, 2023 at 5:41 AM

atmospheric vented gas furnace? if so it's providing make up air for combustion, and yes, it's necessary. Without it you might suck exhaust and CO back into you home.

EdwardJMunson OP t1_j6gwkhe wrote on January 30, 2023 at 5:58 AM

But shouldn't there be a damper or a vent cover or something? It's just a straight duct to the outside.

jinbtown t1_j6gx6j9 wrote on January 30, 2023 at 6:05 AM

Not necessarily, but a lot depends on your local code and requirements

EdwardJMunson OP t1_j6h28eb wrote on January 30, 2023 at 7:04 AM

Interesting. I'll have to check into it a bit more.