Direct vent, or sealed combustion water heaters, depending on where it will be located, allow the pipe to be terminated at an outside wall, or the roof depending on which is easier.: I wish to install a gas hot water service in my new apartment (for efficiency, convenience and size). My problem is, it is almost impossible to flue the exhaust to the outside, and once outside, my understanding is that I must then run the flue to the roof (three floors up!) : Are there any gas systems which can get around this problem?
