A stainless wall-mount chimney range hood on a tiled wall in winter light fills the upper half of the frame, faint cold condensation beading on the range hood's lower edge and a fine mist visible drifting down from the canopy, the burners below off.

Cold Draft or a Flapping Damper Through the Range Hood

A range hood cold air draft is felt as chill air falling from the canopy onto the burners with the fan off, a flapping or tapping from the duct on windy days, or a smell of the outdoors in the kitchen.

(844) 398-3217

Mon–Sat, 8am–8pm

5 checks before you book
5 questions that narrow it
6 causes, cheapest first

Book a visit

Three short steps, about a minute.

or call (844) 398-3217

What it
usually means.

Every ducted hood is a hole from the kitchen to the outside, and it is closed by a backdraft damper: a light flap, or a pair of them, that the fan's airflow pushes open and gravity or a spring pushes shut again. There is often one at the hood's outlet and another at the outside cap. When the damper sticks open with grease, bends, loses its spring, or was never fitted, cold air sinks down the duct and pours out of the canopy, and on windy days the flap can bang back and forth. A wall cap facing the prevailing wind lets gusts push air in against a weak flap. A tight house makes it worse: when a dryer, a bath fan or a fireplace pulls air out, the house draws it back in through the easiest path, often the hood duct. The same open path lets warm, moist air from the house reach the cold duct and condense, which is where drips and mildew begin. Most of this is fixed at the damper, the cap and the duct; the damper inside a chimney cover or on the roof is reached by a technician, not by an owner on a ladder.

Looking up into the open underside of a stainless range hood in a US home kitchen with its filters removed, the round backdraft damper at the top of the range hood's blower outlet visible with its two metal flaps half open, a gloved hand holding a new damper beside it, soft light.

The 6 causes, cheapest first

Answer these first

Is the draft felt with the fan off, and is it worse on windy or cold days?

Is there a tapping or flapping sound from the duct, or at the outside cap?

Does the draft get stronger when a dryer, a bath fan or a fireplace is running?

Is there condensation or dripping from the hood in winter?

Does the duct exit through a wall or the roof, and which way does the cap face?

Check these
before you book.

Range hood cold air draft: 5 checks, and none of them costs anything.

Feel for the draft at the canopy with the fan off, on a calm day and on a windy one.

From the ground, look at the outside cap to see whether its flap is there and closes when the fan is off; do not climb to it.

Note whether a dryer, bath fan or fireplace was running when the draft was strongest.

Also worth checking

Run the hood briefly on high and listen for the damper opening and closing when it stops.
Book a visit with the model number from behind the filters and where the duct exits.

How soon does it need a visit?

Not urgent, but a damper that stays open wastes heat, lets in moisture and can lead to drips and mildew in the duct. Book whenever the week allows.

The causes,
cheapest first.

6 things cold draft or a flapping damper through the range hood turns out to be, from another appliance pulling air in through the duct to gaps in the duct joints.

The cost guide

01 no repair

Another appliance pulling air in through the duct

A dryer, bath fan or fireplace running at the same time can draw outside air back through the hood duct. Cracking a window while they run eases it; the house may also need a make-up air path.
No repair: check it yourself
02 low

A damper stuck open with grease

The flap at the hood's outlet can glue itself open with grease. It is cleaned and freed, and a bent flap is replaced.
Fixed by range hood damper and duct repair
03 low to moderate

A weak or missing damper at the cap

The outside cap's flap can break, lose its spring or be missing. A cap with a working flap, sized to the duct, is fitted.
Fixed by range hood damper and duct repair
04 low to moderate

A cap facing the wind

A wall cap on the windward side takes gusts straight into the duct. A cap with a stronger flap or a hooded design holds up better.
Fixed by range hood damper and duct repair
05 moderate

A damper motor that stopped working

Some hoods and makeup air systems use a motorized damper that opens and closes with the fan. When the motor or its signal fails, the damper stays open or shut.
Fixed by range hood damper and duct repair
06 moderate

Gaps in the duct joints

Joints that were never sealed, or ones that pulled apart, let cold attic or wall air into the duct and on down to the canopy. They are sealed with foil tape rated for the job.
Fixed by range hood damper and duct repair