How Do Gas Wall Heaters Work. Wall heaters operate by heating a stream of air moving through the unit by convection. The second type of gas wall heater is the conventional vented wall heater which directs the combustion gases to the atmosphere with the use of a single or double wall gravity vent pipe.
Generally speaking, gas water heaters are more expensive to buy than electric models, but cost less to operate because gas is cheaper than electricity.
Instead, the oxygen that is needed to fuel the combustion process for heat is taken from the air inside of the room in which the unit is placed, and the resulting heat is vented back out directly from the unit. While some of the same principles apply to most heaters, each make and model has subtle variations. What types of central heating systems are available? Tankless continuous flow through hot water heater systems are the most popular type of gas hot water heater.