Vented recessed gas wall heaters release combustion fumes outside of the space being heated to keep the air clean. Heaters with a gravity heating method use convection heating to create currents that warm and circulate the air, but they can also be converted to forced air with an optional blower. Heaters with a fan forced heating method use a fan to push out and circulate hot air throughout the space. These heaters recess in walls to produce heat for small areas without taking up limited floorspace.