Find a 24/7 HVAC Technician in St. Louis, MO
When your AC or heat fails on the worst day of the year, every hour matters. Connect with an independent local HVAC pro — our phone line is open 24/7.
By Gyanesh Gulshan — Founder, Cool Call Pro
HVAC emergencies in St. Louis
Call Now — (844) 582-179524/7 call line · call to check availability in St. Louis
AC out, blowing warm, or iced over
Outdoor unit silent · indoor blower running but warm air · ice on the refrigerant lines · short-cycling on/off. Possible causes range from electrical parts (capacitor, contactor) to a refrigerant problem — both need a technician to diagnose.
Furnace not igniting or blowing cold
Furnace won't ignite · blowing cold air · short-cycling · burning smell on first startup. If you smell gas, leave the building right away without flipping switches or using phones inside, then call 911 or your gas utility’s emergency line from outside.
Banging, screaming, or grinding outdoor unit
Loud bangs · metal-on-metal screaming · grinding or rattling from the outdoor unit. Possible causes include a failing fan motor, a loose blower wheel, or worn compressor bearings. Turn the system off at the thermostat and call a technician.
How Cool Call Pro works in St. Louis
24/7 St. Louis call line
Our phone line is open 24/7. Calls are routed to independent HVAC providers in the St. Louis area where one is available; hours, weekend and holiday coverage, and overnight surcharges are set by each provider.
Call to check availability
Provider availability varies by address and time of day, so call to check availability in St. Louis. The neighborhoods and ZIPs listed for this page are in the Services & service area section below.
Check licenses yourself
Cool Call Pro does not check contractor licenses or insurance. Licensing is set locally in Missouri — check with your city or county before you hire. Missouri rules are in the local data section below.
St. Louis's mixed-humid climate & your HVAC
This Zone 4A (Mixed-Humid) climate splits the year between heating and cooling load. Federal SEER2 13.4 (North Region) minimum applies to new AC equipment. A heat pump handles both heating and cooling from one outdoor unit.
Avg summer high
IECC zone (mixed-humid)
Avg winter low
Federal SEER2 minimum
Days/yr above 90°F
Days/yr below 32°F
St. Louis had an estimated 278,144 residents on July 1, 2025. In St. Louis, the median home was built in 1938 with a current median value of $185,100. Around 45% of homes are owner-occupied. About 68% of households heat with natural gas vs. 30% electric. The Missouri grid averages $0.12/kWh. Sources: U.S. Census population estimates · U.S. Census ACS 2019–2023 5-year tables B25035 · B25077 · B25003 · B25040 · U.S. EIA state rates.
Read our guide on heat pump guide.
HVAC in St. Louis, MO: local data & sources
Every numerical claim below references a federal, state, or municipal primary source — NOAA climate normals, U.S. Census ACS, the Missouri licensing authority, and your local utility's published rebate program.
NOAA NCEI 1991–2020 Normals
St. Louis Lambert International Airport (KSTL) is the NOAA reference station for the city. Per the NOAA NCEI U.S. Climate Normals 1991–2020 (station USW00013994), St. Louis records an annual mean temperature of 57.4°F, approximately 4,432.9 annual heating degree days against 1,713.0 cooling degree days, 41.70 inches of annual precipitation, and 16.6 inches of annual snowfall. The 2.6:1 HDD-to-CDD ratio and high summertime humidity define St. Louis as a classic Zone 4A mixed-humid climate — both heating and cooling matter meaningfully, and properly sized equipment must manage both seasons without sacrificing summer dehumidification.
U.S. Census ACS 2023 5-Year
The U.S. Census Bureau ACS 2023 5-year estimates (Tables B25040 House Heating Fuel and B25035 Median Year Structure Built for St. Louis city, Missouri) report 144,450 occupied housing units with a median year built of 1938. Heating-fuel distribution: 67.8% utility natural gas (97,890 units), 29.6% electricity (42,801 units), 2,013 units on bottled/LP gas, and small numbers on wood (170), fuel oil (142), and solar (70). The 1938 median year built means half of St. Louis’s homes predate World War II, which creates real retrofit challenges: undersized ducts, heritage boilers and radiators, masonry construction, and knob-and-tube electrical systems that constrain modern HVAC installation.
St. Louis Municipal Code
Missouri does not issue a statewide HVAC contractor license. Instead, the City of St. Louis issues its own municipal mechanical contractor license. Per the City of St. Louis Code of Ordinances (Municode) referenced by the Building Division: “A new Mechanical Ordinance, Number 70800, requires that all residential replacement or new heating/cooling units be installed by a mechanical contractor licensed in the City.” Permits are required for “boilers, furnaces, exhaust fans and hoods, and ventilation systems.” Contractors new to the City must procure a city license through the Building Division Mechanical Section at 314-622-3313. For homeowners, verifying a contractor’s City-issued license before authorizing installation work is the critical due-diligence step in St. Louis — more important than in states with a statewide board, because the municipal license is the only formal credential.
DSIRE Database (NCSU + DOE)
St. Louis is served by Ameren Missouri for electricity and Spire for natural gas. Both utilities administer residential energy-efficiency rebate programs for high-efficiency HVAC equipment, smart thermostats, and weatherization. Because utility rebate amounts change annually and program pages sometimes block automated checks, the most reliable way to see current dollar amounts is the ENERGY STAR Rebate Finder (EPA) with a St. Louis ZIP code, or the DSIRE database filtered to Missouri residential incentives. Permit fees for residential mechanical work in the City of St. Louis are set by the Building Division; contact the Mechanical Section directly for the current fee schedule as amounts are updated periodically.
The federal Section 25C Energy Efficient Home Improvement Credit was terminated for installations placed in service after Dec 31, 2025 by the One Big Beautiful Bill Act (Public Law 119-21). Check your state energy office and utility for current rebate programs. See our HVAC financing options for what's still available.
Services & service area
Services you can ask about
- Emergency AC Repair in St. Louis
- Furnace Repair & Heating Service in St. Louis
- Heat Pump Installation & Dual-Fuel Systems
- Central Air Conditioning Installation & Replacement
- HVAC System Maintenance & Seasonal Tune-Ups
Neighborhoods & ZIPs listed for St. Louis
- Tower Grove South
- South Hampton
- Bevo Mill
- Shaw
- Holly Hills
- ZIP codes: 63116, 63109, 63110, 63118, 63104
HVAC repair costs: national ranges for St. Louis, MO homeowners
Cool Call Pro editorial estimates of typical U.S. prices from our 2026 cost guide — not quotes and not St. Louis-specific. Actual price varies by provider and complexity.
Diagnostic / service call
$65–$150
Some providers credit it toward the repair — ask when you call
Minor AC repair
$75–$500
Capacitor, contactor, thermostat, drain line
Refrigerant recharge
$150–$600
R-410A per recharge; leak fix extra
After-hours surcharge
$100–$300
Added to repair cost on emergency calls
See full repair, install, and replacement ranges in our 2026 HVAC Cost Guide and how we build these ranges →
Ready to talk to an HVAC pro in St. Louis?
Independent technicians · 24/7 call line · Licensing is set locally in Missouri — check with your city or county before you hire
Call Now — (844) 582-1795Disclosure: We are a referral service and may receive compensation for qualified calls. Calls may be routed to an independent provider network and may be recorded. Pricing and availability vary by provider and location.
Frequently Asked Questions — St. Louis, MO
Yes, ensure your contractor files a mechanical permit with the City of St. Louis Building Division (Dept. of Public Safety). Pulling the correct permits protects you as a homeowner and ensures work is inspected to code.
Rebate programs for St. Louis homeowners are summarized, with sources, in the Local Rebates & Permits card above. Confirm current amounts and eligibility with your utility (Ameren Missouri) before scheduling work. The federal Section 25C credit was terminated for installations placed in service after Dec 31, 2025 (One Big Beautiful Bill Act, P.L. 119-21); check your state energy office and utility rebate programs instead.
The neighborhoods and ZIP codes listed for St. Louis are in the ZIPs & Neighborhoods card above. Provider availability varies by address, so call (844) 582-1795 to check availability in St. Louis.
Cool Call Pro’s editorial estimate for a standard AC replacement in St. Louis is $3,500–$7,200, and for furnace installations $2,800–$6,000. These are our own estimates, not quotes or survey data — see how we build cost ranges. Costs vary with system size, efficiency rating, and installation complexity. In Missouri, new AC units must meet a minimum SEER2 13.4 (North Region) rating.
Missouri does not require a statewide HVAC contractor license. Instead, St. Louis requires municipal license. Always verify your contractor’s credentials before authorizing work. For St. Louis residents, permits are filed through the City of St. Louis Building Division (Dept. of Public Safety).