We have had s many as thirty in stock at a time in our warehouse.
Gas waterheaters (natural gas or propane) are atmospheric ventilation models, meaning they use a galvanized vent pipe inserted into a masonry chimney.
Power-vent waterheaters are the same as the atmospheric models, but with a re-engineered exhaust system. The exhaust vent is made from PVC plastic rather than metal, has a blower (black motor on the top) installed to assist the expulsion of combustion by-products, and can be vented through either the roof or a sidewall, when there is no chimney.
Electric waterheaters are as the name state… they would have an electric wire connecting to the top of the waterheater. They would also have one or two access doors (as shown in photo) on the front of the unit.