Doing some research before the inspection. Furnace in garage apparently heats the garage and a family room. There isn’t any appilcation where this is allowed is there?
Thanks in advance!
No. You can do the garage only, but not an interior space with the garage.
David even if there is no return air from the garage? and a fire damper?
A supply register into the garage will pressurize the garage and de-pressurize the house. Both will cause efficiency issues and CO poisoning potential.
Pushing air into the garage will want to find it’s way back to the house. The house, in a low atmosphere will suck all it can from that garage which is even a higher atmosphere than outdoors.
Fire damper will correct the fire barrier issue between the garage and house.
Air quality is still a concern.
I am not discussing code issues, only design issues.
Too much gets past the code department to concern myself with their views.
I am on your side of the fence David The reason i asked i wrote one up and got kicked in the butt because the code guy approved it . At least i can sleep at night .
Ah… another “case in point”! 
I’m used to getting my butt kicked!
If the client wants to listen to the code guy, that’s no longer my problem…
I sleep just fine! 
Wrong is wrong, no matter how many times it’s done wrong, it’s still wrong!
Thanks for the imput, common sense and safety always comes first.