Gas Fitter Practice Test

A commercial forced air furnace uses which form of heat transfer to heat a home?

1. Radiant

2. Conductive

3. Convective

4. Thermal

The correct answer is: Convective

In a commercial forced air furnace, heat is primarily transferred through convection. This process involves the movement of heated air from the furnace throughout the living space. The furnace heats the air within its heat exchanger, and then this warm air is pushed into the rooms of the building by a fan or blower. As the warm air rises and circulates, it displaces cooler air, leading to an even distribution of heat throughout the environment. While radiant heat transfer occurs when heat travels through electromagnetic waves and conductive transfer involves heat moving through direct contact between materials, these are not the principal modes in which a forced air furnace operates. The system is designed to rely on convection, making it the most appropriate choice for this question. In this context, thermal is a broader term that encompasses various forms of heat transfer, but it does not specifically describe how a forced air furnace achieves heating, so it doesn't capture the essence of the question correctly.