Avalon gas stoves are manufactured for safe indoor use. By using direct venting instead of other methods, including B-vents, vent-free and vent-free safety, this type of stove is considered the safest and most energy-efficient style.
Direct venting designs use a double wall pipe. The interior pipe vents exhaust gases outside for safety, while the exterior pipe draws air in for combustion. The inflowing air is warmed as it passes around the exhaust pipe, improving efficiency. B-vents styles vent harmful gases outside, but draw warm air from the room in for combustion, making them less efficient. Vent-free systems have the same efficiency problem and also vent carbon monoxide and carbon dioxide into the room, while vent-free safety systems are essentially the same but have an added oxygen depletion sensor to detect dangerous oxygen levels.