Duct & Dryer Vent Cleaning for Minnesota's Long Heating Season

A long heating season, mostly in climate zones 6 and 7

Under the 2021 International Energy Conservation Code (IECC), most Minnesota counties — including Hennepin, Ramsey, Dakota, Washington and Olmsted — are in climate zone 6A, and much of northern Minnesota, including St. Louis County around Duluth, is in zone 7, the "very cold" zone. Three southeastern counties — Fillmore, Houston and Winona — moved from zone 6A to 5A in the 2021 update. NOAA's state climate summary describes Minnesota winters as cold in the south and frigid in the north.

Most homes heat with a furnace. In the U.S. Energy Information Administration's 2020 Residential Energy Consumption Survey (RECS), a furnace was the main heating equipment in about 73% of Minnesota homes, compared with about 60% nationally. A system that runs much of the year makes regular filter changes worthwhile, but it doesn't mean the ducts need cleaning on a schedule: EPA doesn't recommend routine duct cleaning, only cleaning as needed.

Sources: PNNL for U.S. DOE — Guide to Determining Climate Zones by County: Building America and IECC 2021 Updates (PNNL-33270, 2022); NOAA NCEI State Climate Summaries 2022 — Minnesota; U.S. EIA — 2020 Residential Energy Consumption Survey, state highlights: space heating; U.S. EPA — Should You Have the Air Ducts in Your Home Cleaned?

Basements, older homes, and joist-space returns

Basements are far more common here than in most of the country. RECS 2020 estimates that about 65% of Minnesota homes have a basement, compared with about 30% nationally, and the Census Bureau reports that half of the new single-family houses completed in the Midwest in 2025 had a full or partial basement.

Much of the housing is also old. In the Census Bureau's 2024 American Community Survey, about 15% of Minnesota housing units were built in 1939 or earlier — about 41% in Minneapolis and 42% in St. Paul — compared with 11.5% nationally.

That shapes how ductwork is reached. The U.S. Department of Energy notes that a furnace in the basement is usually easy to find, but also that builders sometimes use the spaces between floor joists as duct runs, especially for returns, and that some homes have no return ducts at all — just an intake grille on the furnace. Finished basement ceilings can hide branch runs, so the estimate notes what can and can't be reached.

Sources: U.S. EIA — 2020 Residential Energy Consumption Survey, state highlights: structural characteristics; U.S. Census Bureau — Characteristics of New Housing: type of foundation in new single-family houses completed; U.S. Census Bureau — American Community Survey 2024 1-year estimates, table B25034 (Year Structure Built); U.S. DOE — Improving the Efficiency of Your Duct System

Snow, ice, and exterior vent hoods

NOAA puts average annual snowfall at 30 to 70 inches over most of Minnesota, with values near 90 inches along the Lake Superior shore. Drifts and ice can cover low exterior vents on any side of a house.

The Minnesota State Fire Marshal advises clearing snow and debris from furnace, dryer, fireplace and oven vents in winter to prevent a carbon monoxide buildup. The Minnesota Department of Commerce adds that outside dryer exhaust vents should be checked monthly to make sure the flapper moves freely and no lint is blocking the opening.

Sources: NOAA NCEI State Climate Summaries 2022 — Minnesota; Minnesota State Fire Marshal — Carbon monoxide poisoning; Minnesota Department of Commerce — Clothes drying tips to save energy and stay safe

Wildfire-smoke summers and filter questions

Smoke from distant wildfires has become part of some Minnesota summers. The Minnesota Pollution Control Agency issued 22 air quality alerts covering 52 days in 2023, beating the previous record of 13 alerts over 42 days in 2021, with smoke from Canadian wildfires behind most of them.

For smoke days, EPA's advice centers on filtration: use a high-efficiency HVAC filter, such as one rated MERV 13, or as high a rating as your system's fan and filter slot can accommodate, and close the fresh-air intake or switch to recirculate if your system has one. EPA notes you may need an HVAC technician to tell you the highest-efficiency filter your system can handle. Duct cleaning isn't a substitute for filtration, and supplying or changing filters isn't part of our service.

Sources: Minnesota Pollution Control Agency — After record number of air quality alerts, even more hazy days expected (2023); U.S. EPA — Wildfires and Indoor Air Quality