Clean Ducts and Clear Dryer Vents for Utah's Heating Season

Mostly cold climate, with a hot-dry corner

On the 2021 climate zone map used for energy codes, Salt Lake, Utah, Davis, and Weber counties are zone 5B, and Summit and Wasatch counties are zone 6B. The Department of Energy's climate-zone guide classes both as cold, a range of roughly 5,400 to 9,000 heating degree days a year. Washington County in the southwest corner, which includes St. George, is the exception: zone 3B, a hot-dry climate where monthly average temperatures stay above 45°F.

In the Wasatch Front counties, that means a substantial heating season for the furnace and ductwork. In Washington County, cooling matters more. The cleaning we do is the same either way; what changes is which season puts the most hours on the system.

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

Furnaces, basements, and newer houses

Utah leans heavily on forced-air heat. In the U.S. Energy Information Administration's 2020 Residential Energy Consumption Survey (RECS), about 90% of Utah homes used a furnace as their main heating equipment, compared with about 60% nationally. A furnace sends warm air through ducts to the rooms, so in most Utah homes the duct system is part of daily life all winter. About 79% of Utah homes also use central air-conditioning equipment.

The same survey estimated that about 57% of Utah homes have a basement, nearly double the national figure of about 30%, and that about 37% of Utah homes were built in 2000 or later, versus about 21% nationwide. About 70% are single-family detached houses.

If your furnace and main duct lines are in a basement, whether that basement is finished makes a big difference to access. Ducts enclosed in finished ceilings can only be reached through existing registers, grilles, and access points.

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

Winter inversions

Utah's Department of Environmental Quality describes wintertime inversions as cold air at the surface getting trapped under a layer of warmer air. The Wasatch and Oquirrh mountains and Traverse Mountain form a basin that holds cold air in the Salt Lake Valley, and DEQ says a typical Utah winter sees about five to six multi-day inversion episodes. Pollutants from vehicles, wood burning, industry, and other sources are trapped near the ground, and fine particle pollution (PM2.5) builds the longer an inversion lasts.

Duct cleaning doesn't remove outdoor pollution. During inversion season, the furnace filter is the part of the system that actually captures particles from the air moving through it, so filter choice and regular filter changes are the practical step, not duct cleaning.

Sources: Utah Department of Environmental Quality — Inversions; U.S. EPA — Should You Have the Air Ducts in Your Home Cleaned?; U.S. EPA — What is a MERV rating?