Derived from the Latin word fornax, meaning oven, a furnace is a large heating appliance designed to evenly distribute heat throughout a building. Furnaces accomplish this by burning fuel internally ...

Gas and oil furnaces burn fuel to provide heat for homes, and that presents a basic problem. Every combustion process produces noxious gases. How do you keep those gases from circulating throughout ...

AI-generated summary reviewed by our newsroom. Read our AI Policy. Furnaces typically fail after 15-20 years; schedule replacement before winter peak. Gas units cost $3,000-$8,000 and offer lower ...