Venting a Dryer That Sits in a Garage

The Garage Is Still Inside the Building

A garage feels like the outdoors with a door on it, which is why so many garage dryers blow straight into the room. The 2023 Florida Building Code, Residential, does not see it that way. Section M1502.3 says dryer exhaust ducts terminate on the outside of the building, and the garage is part of the building. Section M1501.1 adds that exhaust air goes to the outdoors and never into an attic, soffit, ridge vent or crawl space, which rules out the attic over the garage as well.

Whether a hose dumping into the garage is ever acceptable is a separate question, answered in can you vent dryer into attic. This page assumes you want the dryer vented properly and looks at how to get it out.

What Happens When the Duct Stops in the Garage

A dryer moves a lot of warm, wet air. Released in a closed garage, the moisture settles on the coolest surfaces: the door, tools, the car and the underside of the roof deck. Maytag's installation instructions warn that improper venting lets moisture and lint collect indoors and damage paint and woodwork. The lint itself coats shelves and rafters, where it is a ready fuel near the dryer's own heat.

With a gas dryer the exhaust also carries combustion products. Section G2439.1 of the code's fuel gas chapter requires a dryer exhaust to carry the moisture and any products of combustion to the outside of the building. In an attached garage those gases can follow the air into the house through the connecting door.

Three Ways Out of a Garage Laundry

Whatever the route, the duct is smooth 4 inch metal under section M1502.4.1, sized to the 35 foot equivalent length rule or the dryer maker's chart, with every elbow counted.

Only one route crosses into the house, and that crossing has its own rule. Section R302.5.2 of the Florida code says ducts in the garage, and ducts penetrating the walls or ceilings between the dwelling and the garage, are made of at least No. 26 gage sheet steel or another approved material and have no openings into the garage. Section R302.5.3 requires the hole through that separation to be protected as well. A dryer duct that crosses the line has to keep the separation intact, which is one more reason to vent a garage dryer out through the garage's own exterior.

• Through the garage's own outside wall: usually the shortest run, ending in a hood at least 12 inches above the ground and 3 feet from the garage door opening and any window or door, as section M1502.3 and the dryer makers ask.
• Up through the garage ceiling and out the roof: useful when the dryer stands against the wall shared with the house. The duct must pass through the garage attic to a roof cap, never stop in it.
• Back through the house: rarely the right choice, because the duct then has to cross the wall or ceiling that separates the house from the garage.

Gas Dryers in a Garage: Height and Air

The fuel gas chapter keeps a dryer's flame off the garage floor, where cars, mowers and fuel cans sit. Section G2408.2 requires an appliance with an ignition source in a private garage to be raised so the source is at least 18 inches above the floor, unless the appliance is listed as flammable-vapor-ignition resistant. Samsung's manual says gas dryers in residential garages must be raised 18 inches, and GE's instructions add a barrier to protect the dryer from vehicles and a warning not to install it where gasoline or other flammables are stored.

Air supply matters too. A dryer pulls room air in as fast as it pushes exhaust out. Section G2439.5 requires makeup air for installations exhausting more than 200 cubic feet per minute, and section G2407.4 requires it wherever a clothes dryer interferes with the operation of other appliances. In a garage that also holds a gas water heater, a tightly closed garage can leave the dryer and the water heater competing for the same air. Keep the dryer's air supply in mind when the garage is shut up.

Checks You Can Make in Your Own Garage

Maytag points out that some local codes limit dryers in garages and suggests checking with the local building inspector. If you find a duct ending in the garage, a gas dryer sitting on the floor, or a hose running through the house wall, stop using the dryer until it is sorted out, and do not climb into the garage attic alone to chase the duct.

• Follow the hose from the dryer: does it reach a wall collar, or end loose behind the machine?
• Look for lint on the rafters, shelves or the top of the garage door track.
• Go outside while the dryer runs and watch for the hood flap lifting.
• For a gas dryer, check its height off the floor and what is stored near it.
• Note any rust or water stains on the ceiling above the dryer.

Getting a Garage Dryer Vented Properly

We plan garage routes under dryer vent installation: the shortest way out, the right hood, and a duct that stays clear of the house separation. If the dryer is being moved into the garage as part of a remodel, start with how to move a dryer vent. Manufactured homes follow a different federal standard, explained in mobile home dryer vent under home.

Ours is a family-owned, local business, and our experienced crew checks gas dryers for height and air supply as part of the visit. Proudly American, we begin with a free inspection and a written estimate for the route.