How to Clean Your Dryer Vent Before a Minnesota Winter

Clothes dryers cause about 2,900 home fires a year in the United States, and failure to clean is the leading cause, according to the U.S. Fire Administration. Most of those fires start with lint that has built up in the vent line or around the heater. In Rochester the risk climbs from November to March, when dryers run more loads, laundry rooms stay closed and snow can block the outside vent hood.

The good news: a full vent cleaning takes about an hour, needs only a basic brush kit and makes your dryer faster and cheaper to run. This guide covers the warning signs, the exact steps, the vent length rules that matter in older basement laundry rooms and what to do when the outside flap freezes shut.

Quick answer: how often should you clean a dryer vent?

Clean the lint screen after every load and the full vent line at least once a year. Homes with long vent runs, large families, pets or a dryer in a closet should clean every six months. The best time in Minnesota is late October, before heavy winter use and before snow piles against the exterior hood.

Signs your dryer vent is clogged

• Clothes need two cycles to dry, or towels stay damp at the seams
• The top of the dryer or the laundry room feels unusually hot
• A burning or musty smell while the dryer runs
• The outside vent flap barely opens or does not open at all while the dryer runs
• Lint collects around the outside hood or behind the dryer
• The dryer shuts off mid cycle or has blown a thermal fuse

That last sign matters. A blown thermal fuse is the dryer protecting itself from overheating, and the root cause is usually restricted airflow. Replacing the fuse without cleaning the vent means the new fuse will blow again, as we explain in our electric dryer repair guide.

Why Minnesota winters make it worse

Dryer exhaust is warm and full of moisture. When it hits a cold exterior hood, water condenses and can freeze around the flap, especially after a storm when snow drifts against the house. A flap frozen partly shut cuts airflow sharply. Inside, long vent runs through cold basements or crawl spaces collect condensation, which makes lint stick to the duct walls faster. Rochester's older homes often have laundry in the basement with vents that travel 20 feet or more to the outside, which is exactly where buildup hides.

Tools you need

How to clean a dryer vent, step by step

1. 1

   Unplug the dryer

   For a gas dryer, also turn off the gas shutoff valve behind the dryer. Never move a gas dryer far enough to strain the gas connector.

2. 2

   Clean the lint screen and its housing

   Remove the screen, wash it in warm soapy water if it looks waxy from dryer sheets, and vacuum the housing it slides into.

3. 3

   Disconnect the transition duct

   Slide the dryer forward and loosen the clamp holding the short duct between the dryer and the wall. Vacuum the dryer outlet.

4. 4

   Brush from the inside

   Feed the brush into the wall opening, spinning it clockwise with a drill on low speed or by hand. Add rods until you reach the outside. Pull back slowly and vacuum what comes out.

5. 5

   Brush from the outside

   Remove or open the exterior hood and brush back toward the house. Clear any nests, lint mats or ice from the flap.

6. 6

   Inspect and replace bad duct

   Replace plastic or foil accordion duct with semi rigid or rigid metal. Keep the transition duct as short and straight as possible.

7. 7

   Reconnect and seal

   Reattach with clamps and foil tape. Do not use screws through the duct; they catch lint.

8. 8

   Test the airflow

   Run the dryer on air fluff and check that the outside flap opens fully with strong airflow.

How long can a dryer vent be?

Under the International Residential Code, a 4 inch rigid metal dryer exhaust can run up to 35 feet. Subtract 5 feet for each 90 degree elbow and 2.5 feet for each 45 degree elbow, unless the dryer manufacturer's instructions allow more. A basement run with three elbows is therefore limited to about 20 feet of straight duct. Our dryer vent cleaning page has a calculator that checks your run.

What to do when the outside flap freezes

Check the hood after every snowstorm and on very cold mornings. Gently clear snow and ice by hand or with warm water, never with a sharp tool that could crack a plastic hood. If the flap freezes often, a hood with a larger opening or a louvered design that sheds condensation better can help. Keep snow cleared at least a foot around the hood all winter.

When to call a professional

• The vent runs through a ceiling, a second floor or the roof
• You cannot reach the full length with a brush kit
• The dryer still runs hot or slow after cleaning
• The duct inside the wall is crushed, disconnected or plastic
• The dryer has blown a thermal fuse or stopped heating

A professional cleaning includes before and after airflow checks, cleaning the dryer's internal exhaust path and repairing damaged duct or hoods. If your washer is also giving trouble, see our washer and dryer repair guide.