Recently inspected a townhome with drive under garage and finished basement. Two HVAC supply vents were installed in the garage (one directly above a gas water heater flue. I stated the normal safety concerns and recommended a licensed HVAC contractor inspect and correct as needed. Here is what the licensed contractor put in writing on the invoice:
"System is working properly at this time. Ducts in garage are supply vents and have been inplace since time of install. There is no code stating that you can not have supply vents in a garage. To seal the vents off could cause the downstairs Zone to be out of balance and could cause problems in the system operation."
My thoughts are do you want to live with a potential safety hazard or “live” with a balanced sytem.
You are asking for thought so here are mine. He is correct no code against supply duct in the garage. He was more than likely the contractor that installed it do you suspect he might be a little on the biased side.
More than likely would require re-balancing the system so what do it anyway. Only a meat head would install a supply vent over the top of the flue exhaust of a water heater not good engineering practice. I know of no code that requires the exact location of the supply vent but the common sense rule should apply. That is my thoughts and I am sticking to them:D:D
It’s not only dumb but it is against code. What prevents any fumes in the garage from working their way into the duct system and in to the home. The home is usually under a slight negative pressure due to stack effect anyways so now you have a direct connection to the garage. Having a supply to an area that can’t return will cause an even larger negative pressure in the home when the FAU in on.
IRC Section M1601.6- HVAC systems that supply air to the garage shall not supply or obtain air from any other space but the garage. HVAC systems that supply air to the living space shall not supply or obtain air from any other space but the living space.
Building standards require that all ducts in the garage and ducts penetrating the firewall be equipped with fire-dampers or constructed of a minimum of No. 26 gauge sheet steel or other approved material and shall have no openings in the garage. This condition compromises the garage firewall system.
*R309.1.1 Duct penetration. Ducts in the garage and ducts penetrating the walls or ceilings separating the dwelling from the garage shall be constructed of a minimum No.26 gage sheet steel or other approved material *and shall have no openings into the garage.
Also I believe this is referring to duct pipe passing through a garage not a supply or return vent.