HVAC Cost Stats: St. Louis, MO (2026)

St. Louis has some of the oldest housing anywhere in our dataset. The Census Bureau's median year built for the city is 1939 or earlier, which is the oldest category ACS reports (ACS B25035).

Heat and humidity both

Lambert airport averages 4,432.9 heating and 1,713.0 cooling degree days annually. Systems here have to handle a real winter and a muggy summer.

Costs that feed a quote

St. Louis is an independent city, not part of any county. Electric service: Ameren Missouri. Gas: Spire. Permits: City of St. Louis.

See the St. Louis furnace guide, or the full HVAC Cost Stats by Metro (2026).

Housing stock and heating fuel in St. Louis

The St. Louis city limits held 288,512 residents and 144,891 occupied homes in the Census Bureau's ACS 2024 5-year American Community Survey. Utility gas heats 67% of occupied homes and electricity 31%, so most replacements here are gas furnaces paired with a central air conditioner, with heat pumps as the main alternative. Bottled gas or propane heats 1%.

43% of housing units are single-family detached houses and 45% of occupied homes are owner-occupied. Detached, owner-occupied houses are where most whole-system replacements happen, because the owner chooses the equipment and each house has its own system. Apartments and condos more often use packaged units, wall units or building-managed systems.

These are city-limits figures, not metro-wide, and every survey estimate has a margin of error that you can see on the Census Reporter profile linked above. For city-by-city guides across the state, see the Missouri & Kansas HVAC cost guides hub.

Sources: BLS OEWS (SOC 49-9021, May 2025), EIA (state-level), U.S. Census ACS 2020–2024 5-year (B25035), NOAA 1991–2020 Climate Normals; housing and heating-fuel figures from Census ACS (ACS 2024 5-year, tables B01003, B25003, B25024, B25040), accessed October 31, 2026. Data accessed October 30, 2026. Furnace Direct, a DBA of Hamlin Mechanical LLC.