My Kitchen Range Hood Drips Water Onto My Stove in Winter: Why?

If water is dripping from your kitchen range hood in winter, it's almost always condensation forming inside the exhaust duct, not a roof leak. Warm, moist kitchen air cools suddenly as it passes through a poorly insulated duct in a cold attic, water collects, and it runs back down toward the hood.

What's Happening?

• The range hood pushes warm, moist cooking air outside, usually through the roof or a wall, passing through the attic along the way.
• If that duct isn't insulated (or only partially insulated) along a cold stretch, the warm air hits a cold surface and condenses, the same way fog forms on a cold glass.
• Water collects inside the duct, often at a bend or a low point, then runs downhill toward the lowest spot: the hood itself.
• A stuck or poorly adjusted backdraft damper can make it worse by letting cold outside air into the duct more easily.

Is It Dangerous?

• No, it isn't an immediate safety hazard.
• That said, moisture building up in or around the duct can eventually damage cabinets, ceiling finish, or encourage mold if it goes on for more than a winter or two.
• It's not an emergency, but it's not something to ignore indefinitely either.

Most Common Causes

Why This Happens in Quebec

Quebec winters create a huge temperature gap between cooking air (often loaded with water vapor from boiling pasta, simmering broth, or just boiling water) and an attic that can drop well below -20°C. That gap drives far more condensation than in a milder climate, especially in older homes where the range hood duct was added later without proper insulation.

How to Check It Yourself

• Run the hood on high while boiling a large pot of water, and check for drips after 10-15 minutes.
• If you can safely access the attic, look at the duct directly: check for visible condensation, ice, or a torn or missing insulation sleeve.
• Check that the backdraft damper at the exterior outlet opens and closes freely, without sticking.
• Note whether it gets worse on very cold days — that pattern almost always confirms condensation rather than a water intrusion problem.

Can I Ignore It?

You can use a towel or a small container as a temporary fix to protect the stove, but ignoring the cause for more than one season risks damaging ceiling finish or cabinets, and can encourage mold inside the duct or the surrounding attic space.

How Much Does It Cost?

A targeted fix (insulation or a damper swap) usually falls at the low end of these ranges rather than the cost of a full system cleaning.

When to Call a Professional

• If water keeps dripping despite a temporary fix, or if you spot mold in the duct or attic.
• If the backdraft damper looks broken, stuck, or missing entirely.
• If you can't safely access the duct in the attic yourself.
• A ventilation installer can properly insulate the duct, adjust or replace the damper, and confirm the full run meets current standards.

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