My furnace and water heater will be enclosed by 3 walls: one to the living area, one to the hallway, and one to a bedroom. The rear of this utility room is partially open to the storage room, basically you can walk between this room and the storage room. The furnace is a 92% efficiency which pulls combustion air from inside. I will be installing a louvered door to this room as well. My question is can I place a cold air return in the wall which separates the living area and the furnace? This intake would be around the corner from the louvered door for the utility room. I've read about backdrafting and CO2 gasses but I'm not sure if that applies in this case. It will, however, be directly behind the furnace so it will be easy to tie into the cold air return.