Definition
A furnace is a forced-air heating system that burns fuel (usually natural gas in West Michigan) or uses electric heat to warm air, then distributes it through ductwork with a blower. It's the most common primary heat source in the Grand Rapids area. Furnace efficiency is rated in AFUE, and the blower often doubles as the air handler for a central air conditioner.
Why this matters for your home
Because the furnace carries the load through our long heating season, its efficiency, sizing, and condition have an outsized effect on comfort and bills. Annual maintenance also protects the heat exchanger, the safety-critical part that separates combustion gases from your indoor air.