Natural-vent gas fireplaces, a.k.a. B-vent fireplaces, draw air from inside the home to feed the flames, then vent combustion gases up through a chimney. In this way, they function like a ...

Gas fireplaces, including inserts, can be direct-vent or ventless. Direct-vent systems are usually more expensive and less energy-efficient since heat escapes up the chimney. Unvented or vent-free ...