Colorado Air Duct and Dryer Vent Cleaning, Registers to Vent Hood

Climate zones from the plains to the high country

Colorado spans several climate zones. On the 2021 climate zone map used for energy codes, the Front Range counties — including Denver, Adams, Arapahoe, Boulder, Douglas, El Paso, Jefferson, Larimer, and Pueblo — are zone 5B: dry, and within the range the Department of Energy's climate-zone guide classes as cold, roughly 5,400 to 9,000 heating degree days a year. Mountain counties such as Summit, Lake, Grand, Gunnison, Pitkin, and Routt are zone 7, very cold, at roughly 9,000 to 12,600 heating degree days. A few southeastern counties, including Baca, Las Animas, and Otero, are mixed-dry zone 4B.

Across most of the state, that adds up to a long heating season, so the ductwork in a forced-air home carries warm air for much of the year.

Source: PNNL / U.S. DOE Building America — Guide to Determining Climate Zones by County (PNNL-33270, 2022)

Snow and exterior vents

Snow is a regular part of the heating season along the Front Range. The National Weather Service office in Boulder puts Denver's long-term average seasonal snowfall at about 56.6 inches, based on records from 1882 to 2025, with snow possible from fall well into spring.

That matters for anything that vents through a wall near the ground. USFA's carbon monoxide guidance includes keeping vents for the dryer, furnace, stove, and fireplace clear of snow and other debris, and Xcel Energy advises clearing exhaust vents for natural gas appliances of snow and ice so exhaust gases can escape outdoors.

Sources: National Weather Service Boulder — History of Snowfall Observations at Denver; U.S. Fire Administration — Carbon Monoxide Poisoning Prevention; Xcel Energy — Keep meters and exhaust vents clear of ice and snow (Oct. 2022)

Basements, furnaces, and not everyone has central air

In the U.S. Energy Information Administration's 2020 Residential Energy Consumption Survey (RECS), about 51% of Colorado homes had a basement, compared with about 30% nationally, and about 77% used a furnace — a system that sends warm air through ducts — as their main heating equipment. About 9% heated mainly with a steam or hot-water boiler, which supplies radiators, convectors, or pipes rather than air ducts.

Cooling is more mixed. About 82% of Colorado homes used some air-conditioning equipment, but only about 57% used central air (including central heat pumps), below the national figure of about 67%, and about 20% used individual units such as window units or ductless mini-splits. So some Colorado homes have ducts that carry heat in winter and sit idle in summer.

If your furnace and main duct lines are in a basement, whether it's finished affects what we can reach. About 25% of Colorado homes were built in 2000 or later, and about 63% are single-family detached houses.

Sources: U.S. EIA — Highlights for structural characteristics of U.S. homes by state, 2020 (RECS); U.S. EIA — Highlights for space heating in U.S. homes by state, 2020 (RECS); U.S. EIA — Highlights for air conditioning in U.S. homes by state, 2020 (RECS); U.S. EIA — RECS terminology