Heating and Cooling in St. Louis County, MO

Heating and cooling in St. Louis County, MO is regulated at two levels. Unincorporated communities such as Spanish Lake, Lemay and Mehlville fall under county rules, while cities such as Clayton, University City and Jennings run their own permit offices. Kenan Corporation is based at 927 Broadhead Lane in far north county, and Clayton, the county seat, is about 35 minutes away in normal traffic. That drive is the first fact a county homeowner should know about us.

Who licenses HVAC contractors in St. Louis County

Missouri has no statewide HVAC or mechanical contractor license, so counties and cities decide. In St. Louis County, mechanical licensing runs through the Department of Transportation and Public Works at 41 S. Central Ave. in Clayton, where the Mechanical Licensing Clerk takes calls at (314) 615-7096. A master mechanical license is reported to need 7,500 hours plus a county exam, according to Start Business By State, and the county posts a list of its licensed mechanical contractors.

County permits follow the 2015 International Residential Code as amended for one- and two-family homes. A permit is needed to install, alter, repair or replace heating, air-conditioning or duct systems, and filter changes and refrigerant recharges are not permit work. Ask any contractor, including us, for the license number the jurisdiction requires, and get the permit holder named in the written quote.

The county's housing mix, from 1939 brick to 1960s ranches

The Census Bureau's 2020-2024 American Community Survey counts 446,192 housing units in the county, with a median build year of 1969. About 43,000 date to 1939 or earlier, 53 percent were built before 1970, and only 11 percent since 2000. Seventy-two percent are detached houses and 23 percent are in multi-unit buildings.

That mix explains the repair calls. Utility gas heats about 75 percent of occupied homes, so furnace faults dominate winter. Electricity heats 23 percent. Inner-ring brick houses may still have boilers, and mid-century ranches in places like Lemay and Affton have the oldest ducts. The services below match that pattern.

Cities in the county where we list a page

We list pages for Spanish Lake, Ferguson, Florissant, Hazelwood and Jennings in the north. In the center and west we list University City, Clayton, Richmond Heights, Maplewood, Shrewsbury, Creve Coeur, Chesterfield, Ballwin, Kirkwood and Webster Groves. In the south we list Lemay, Affton, Mehlville and Oakville.

North to south: the drive and the age of the houses

The oldest housing sits in the center and north, the newest in the west, and the drive stretches the farther west or south you go. These medians come from the 2020-2024 American Community Survey, except where Point2Homes is named.

The oldest equipment sits in the north and center, where repair-before-replace decisions come up most. Chesterfield and Ballwin are about 50 and 55 minutes out in normal traffic, so call early in the day for the west end.

How a county visit works from the north end

Call with the address, the equipment type and what it did. The technician diagnoses first, explains the cause plainly and gives a clear, upfront quote before work starts, and we recommend a repair whenever a repair is the sensible fix. The guide to choosing an HVAC contractor in St. Louis lists the questions worth asking any company.

Rentals, apartments and light commercial buildings

Thirty-one percent of occupied county units are rented, and 23 percent of all units sit in multi-unit buildings, according to the same survey. In Clayton the multi-unit share is 65 percent. In a rental, the owner or property manager normally authorizes the repair, so ask for the written quote to be addressed to them.

Permit paths differ by building type. Maryland Heights lets a contractor replace a furnace or condenser like-for-like on a house without plans, but sends commercial and multi-family mechanical work to the county. Unincorporated addresses can use the county's no-plan mechanical permit for like-for-like swaps, according to county Public Works.

Permit notes and local landmarks

Municipal rules vary. The City of Maplewood says it does not issue mechanical permits and sends them to St. Louis County Public Works at 314-615-3867, while Clayton and Jennings run their own. Ameren Missouri supplies electricity and Spire supplies gas across most of the county, with one wrinkle: Kirkwood runs a municipal electric utility for about two-thirds of its city, so Ameren's rebate chart does not reach every county address. The Missouri River forms the north edge and the Meramec River most of the south edge, while I-70, I-270 and I-44 mark the county's informal north, west and south regions. See AC repair and furnace repair for the most common calls.