Excuse me that this is a little out of my normal realm of commercial construction. We are stringently required to exhaust our kitchens, gas HWT, and our HVAC systems 10' from an operable door or window in commercial and multi-family units. Does this apply to a SFR? I have become involved as a consultant on various issues of a log home, and the HVAC contractor does not seem to own a code book, or is at least reticent to produce one. I am concerned about the exhaust gas of a furnace and HWT exiting the house directly above a 5-0 x 6-8 door, and the possibility of CO and CO*2 being reintroduced into the living area.