Atmospheric Vent
- Most common venting style. Also known as "Chimney Vent."
- Uses surrounding air for combustion and exhausts through the flue.
- Vents with B-vent or lined chimney.
- Must use a draft diverter.
Direct Vent
- Uses outside air for combustion and exhausts to the outside (concentric vent) (pipe within a pipe).
- Vent goes out of the wall, not through the ceiling.
- Does not require any power (standing pilot).
Power Vent
- Uses inside air for combustion and vents either horizontally or vertically using PVC, CPVC or ABS material.
- Uses 1 pipe for venting the exhaust.
- Requires power to vent exhaust (blower motor assembly).
Power Direct Vent
- Uses a twin pipe system, pulling air from the outside for combustion and venting exhaust to the outside with a separate pipe (sometimes concentric).
- Typically installed in applications where there is a lack of combustible air.
- Requires power for intake and exhaust (blower motor assembly).