Snow, Ice, and Dryer Vents: A Colorado Winter Checklist

Why snow matters for dryer vents here

The National Weather Service in Boulder puts Denver's long-term average seasonal snowfall at about 56.6 inches, and most Front Range counties sit in cold climate zone 5B on the energy-code map, with mountain counties colder still. If your dryer vents through an exterior wall, a hood near the ground or on the side of the house where drifts form can be covered after a storm — or buried when a driveway or walk is shoveled.

Sources: National Weather Service Boulder — History of Snowfall Observations at Denver; PNNL / U.S. DOE Building America — Guide to Determining Climate Zones by County (PNNL-33270, 2022)

After a storm: what to check outside

USFA's carbon monoxide guidance includes making sure vents for the dryer, furnace, stove, and fireplace are clear of snow and other debris. USFA's dryer safety tips also say to make sure the outdoor vent covering opens when the dryer is operating.

• Find every exhaust vent on the outside of the house — dryer, furnace, water heater — before winter, so you know where to look after a storm.
• Clear snow and ice away from the dryer hood by hand or with a soft brush.
• Run the dryer and watch the flap: it should open and you should feel air coming out.
• Avoid piling shoveled snow against the wall where vents exit.

Sources: U.S. Fire Administration — Carbon Monoxide Poisoning Prevention; U.S. Fire Administration — Clothes Dryer Fire Safety (flyer)

Gas dryers and carbon monoxide

USFA includes dryer vents in its carbon monoxide prevention guidance. Xcel Energy's winter advice covers the same hazard for natural gas appliances such as water heaters, furnaces, stoves, and fireplaces: clear their exhaust vents of snow and ice so exhaust gases can escape outdoors and carbon monoxide doesn't build up.

Clearing the hood is something you can do yourself. Anything involving the gas line or gas connection is a job for a qualified gas appliance technician; we clean vents and don't do gas work.

Sources: Xcel Energy — Keep meters and exhaust vents clear of ice and snow (Oct. 2022); U.S. Fire Administration — Carbon Monoxide Poisoning Prevention

Lint is the year-round issue

Snow is a seasonal blockage; lint builds up all year. USFA lists failure to clean as the leading factor contributing to home clothes dryer fires from 2018 to 2020, and its safety tips include cleaning the lint filter before and after each cycle, cleaning behind the dryer where lint can build up, and checking that the venting behind the dryer isn't damaged, crushed, or restricted.

Sources: U.S. Fire Administration — Appliance and Electrical Fire Safety; U.S. Fire Administration — Clothes Dryer Fire Safety (flyer)

When to call for a cleaning

If the outside hood is clear but the flap barely opens, you feel little airflow, or the transition duct behind the dryer is crushed, the restriction may be inside the vent. That's when a professional cleaning makes sense. Our cleaning covers the transition duct, the vent run, and the exterior hood. Cleaning lowers lint buildup, but it can't promise to prevent every fire, and replacing crushed duct or rerouting a vent is installation work outside our cleaning service.

Source: U.S. Fire Administration — Clothes Dryer Fire Safety (flyer)