What is the difference between power vent and direct vent?

Three ways a gas tank gets rid of exhaust

Every gas water heater makes exhaust that has to leave the house. The vent type decides how it leaves, where the burner gets its air, and where the heater can sit.

Type	Exhaust moved by	Combustion air from	Electricity	Typical vent
Atmospheric (standard)	Natural draft up a flue	The room	None on pilot-powered models[6]	Metal flue through the roof or into a chimney
Power vent	Electric blower[1]	The room[1]	120 volts[1]	PVC, ABS or CPVC; vertical or horizontal; up to 150 equivalent feet on Rheem's line[1]
Direct vent	Natural draft through a sealed vent	Outdoors, through the outer pipe[2]	None (pilot-powered control)[2]	Short pipe-in-pipe vent out a side wall[2]
Power direct vent	Electric blower	Outdoors, through a second pipe[3]	120 volts[3]	Two plastic pipes (2 or 3 inch), vertical or horizontal[3]

Power vent

A power vent heater has a blower on top of the tank. Rheem describes its Performance power vent line as using indoor air for combustion while the blower exhausts the flue gases^[1]. Because the fan pushes the exhaust, the vent can be plastic pipe that runs sideways, with long runs. Rheem's line allows up to 150 equivalent feet, with vertical or horizontal termination^[1].

Where it fits: basements or interior rooms with no chimney, homes where the old masonry chimney is being retired, or a heater that has to move away from an outside wall.

Tradeoffs:

• It needs a 120-volt outlet, and no power means no hot water^[1].
• The blower makes some noise.
• It still uses room air, so the room needs enough air for combustion.
• It costs more. HomeGuide puts power vent gas models at $350 to $500 more than direct vent models, because of the blower and wiring^[5].

Direct vent

A direct vent heater is sealed off from the room. Bradford White's spec sheet explains that all air for combustion comes directly from outside: a pipe-in-pipe vent draws air in through the outer pipe and sends exhaust out through the inner pipe^[2]. Its standard models use a pilot-powered control and need no external electricity^[2].

Where it fits: a tight, well-sealed home, a closet or small room with little air, or anywhere you do not want the heater pulling conditioned indoor air.

Tradeoffs:

• The vent is short and has to exit a side wall. Bradford White's solid vent kits allow up to 8 feet vertical and 8 feet horizontal, with horizontal termination only^[2].
• So the heater has to sit close to an outside wall.
• It keeps working in a power outage on pilot-powered models^[2].

Power direct vent

This combines the two. Bradford White's power direct vent models use a twin-pipe system: one pipe brings combustion air in from outside, and the other sends exhaust out, moved by a blower^[3]. The pipes can be 2 or 3 inch PVC, ABS or CPVC, run vertically or horizontally, and the intake run may not be longer than the exhaust run^[3]. Bradford White calls these ideal for tightly insulated homes and additions that lack enough air for combustion^[3].

It gives you the placement freedom of a power vent and the sealed combustion of a direct vent. It also carries both downsides on cost and needs 120-volt power^[3].

Why sealed combustion matters in some homes

A standard atmospheric heater relies on a natural draft and on room air. DOE's Building America guide warns that relying on indoor combustion air is "highly discouraged," because whole-house fans or other high-volume exhaust systems can cause back-drafting of the water heater and a fire hazard^[4]. Back-drafting can also pull exhaust, including carbon monoxide, into the room.

That is the main reason plumbers suggest direct vent or power direct vent in tight new homes, in additions, or where a big kitchen exhaust hood or a whole-house fan was added. A plain power vent fixes the vent route, but it does not change the air supply, since it still draws from the room^[1].

Cost picture

HomeGuide's January 2026 national figures^[5]:

Item	Typical range
Standard 40 to 50 gallon tank, installed	$600 to $3,100
Power vent premium over direct vent	$350 to $500 more
Venting installed for the first time	$500 to $1,500 extra
Replacing existing venting	$100 to $600 extra

A power vent swap in a house that never had one may also need a new outlet near the heater. Ranges are national and not quotes.

Homeowner checks

• Know which type you have. A blower on top with plastic pipe means power vent. A short pipe-in-pipe vent through the wall beside the tank means direct vent. A metal flue with a gap at the draft hood means atmospheric.
• Keep the outside vent clear of snow, leaves, nests and plantings.
• On a power vent, check that the heater is plugged in and the outlet has power before calling for no hot water.
• Install carbon monoxide alarms and keep stored chemicals away from any gas heater.

If you smell gas, leave the home without using switches or phones, and call the gas utility or 911 from outside^[7].

When to call a pro

• Any change of vent type, vent route or heater location: it needs a permit and a licensed plumber.
• Exhaust smell, soot or scorch marks at the heater or the vent, or a CO alarm.
• A power vent blower that hums, trips, or shows a fault light.
• A cracked, sagging or disconnected vent pipe on any type.