Andrew Zoellner Fri, 5 June 2026 at 12:15 pm UTC 17 min read Add Yahoo as a preferred source to see more of our stories on Google. (Andrey_Popov/Shutterstock) A metal exhaust pipe extends from a wall, with a vented cover at the end, situated near greenery and a tree in the background. Hot air goes up-cold air goes down This guy must have decided to put a ceiling-hung gas furnace in his garage. But he should have read the instruction manual on how to install the gas heater.