Which gas appliance typically requires a venting system?

A gas furnace requires a venting system primarily because it burns fuel to generate heat for a home. The combustion process produces gases, including carbon monoxide, that can be hazardous if not properly vented. A venting system is essential to direct these exhaust gases safely outside the building, preventing the accumulation of harmful fumes indoors.

In contrast, while a gas oven and gas water heater also produce combustion gases, they may be designed for either direct venting or vent-free operation depending on specific models and installation environments. A gas grill typically operates outdoors and is designed to dissipate any combustion products into the open air without the need for a complex venting system. Therefore, a gas furnace stands out as the appliance that consistently necessitates a dedicated venting system to ensure safety and compliance with building codes.