Gas water heaters that draw combustion air from outside through an intake pipe are referred to as?

The correct answer is that gas water heaters that draw combustion air from outside through an intake pipe are referred to as direct vent water heaters. These heaters are specifically designed to ensure that the combustion process uses air from outside the home, which helps to increase efficiency and safety. Direct vent systems prevent backdrafting, where flue gases can accidentally be drawn back into the living space, thus reducing the risk of carbon monoxide entering the home.

Direct vent water heaters have a two-pipe system, one for intake and one for exhaust, allowing for a balanced and controlled combustion environment. This design is beneficial because it does not rely on indoor air for combustion, making it suitable for tightly sealed homes where indoor air may be limited.

On the other hand, conventional and traditional water heaters typically draw combustion air from the premises rather than from the outside, which can lead to inefficiencies and potential health hazards in poorly ventilated areas. Condensing water heaters are a type of water heater that utilizes the heat from exhaust gases to preheat incoming water, but they may not necessarily utilize direct venting methods.