Which type of heater is not commonly recommended for bathroom installation?

The choice of a direct fired heater is often discouraged for bathroom installations primarily due to safety concerns. Direct fired heaters typically utilize an open combustion process, which can introduce potential hazards in enclosed or humid spaces like bathrooms. The risk of gas leaks and the production of combustion byproducts, such as carbon monoxide, poses significant health risks to occupants. Additionally, the moisture-laden environment of a bathroom can lead to increased corrosion and deterioration of a direct fired unit, making it less suitable for such locations.

In contrast, other types of heaters like forced draft, in-wall electric, and direct vent designs are often considered safer and more efficient for use in bathrooms. Forced draft heaters usually have mechanisms to ensure proper venting of combustion gases away from the living space. In-wall electric heaters are safe because they do not rely on combustion, thus eliminating the risk of gas-related issues. Direct vent heaters are specially designed to draw air from the outside for combustion and ventilate exhaust gases directly outside, which minimizes indoor air quality concerns as well as safety hazards.