Furnace Replacement Cost in St. Louis, Missouri
Furnace replacement in St. Louis runs about $5,400 for a typical job. Basic installs start near $3,000. High-efficiency equipment with duct or electrical work can reach $7,300.
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St. Louis Weather and HVAC Load
NOAA's 1991-2020 climate normals put St. Louis at 4,291 heating degree days and 1,769 cooling degree days per year. Heating is the bigger job here, and furnaces and heat pumps in St. Louis put in far more hours than the air conditioner. Count on roughly 79 nights below 32°F and 47 afternoons past 90°F in a typical year. Snowfall averages about 14 inches. For a 2,000 sq ft house, this climate points to a heating load somewhere near 55,000 BTU/h. Treat that as a starting number. A Manual J calculation will move it up or down based on insulation and windows.
| Heating degree days / year | 4,291 |
|---|---|
| Cooling degree days / year | 1,769 |
| Nights at or below 32°F | 79 |
| Days above 90°F | 47 |
| Average low / high | 48.9°F / 67°F |
St. Louis Housing Stock
Half the homes in St. Louis were built before 1938 (Census ACS median), so the typical house is about 88 years old. Houses that old often still have duct runs sized for an old coal or oil furnace and 60- or 100-amp electrical panels. Both can add cost when new equipment goes in. Owners live in 45.4% of occupied homes, roughly 66,000 households. The median home value is $185,100, and median household income is $55,279. We use both figures to adjust labor and pricing for this page.
NOAA storm reports for St. Louis city show 7 hail days and 12 days with damaging thunderstorm winds over the six years from 2020 to 2025. The largest hail reported was 2 inches across. Storms here are more likely to cause power surges than coil damage, so a surge protector on the outdoor unit is worth the small cost.
When Replacement Makes Sense
- A tech found a cracked heat exchanger, or the CO detector has gone off
- The furnace is 15 to 20 years old or more
- Gas or electric bills keep climbing even though usage hasn't changed
- A repair quote runs past a third of the cost of a new unit
What Moves the Price
- AFUE rating: a basic 80% unit vs. a 96% condensing furnace
- New PVC venting if you move to a condensing model
- BTU size, which should come from a Manual J load calculation
- Condition of the existing ductwork and any changes it needs
- Permit and inspection fees, which the local building department sets
- Single-stage, two-stage or modulating gas valve
For St. Louis we lowered the national figures about 7%, based on local income, home values and climate-based equipment sizing. Get at least three written quotes; real bids can land outside this range.
What the Quote Should Cover
- The new furnace, filter rack and thermostat wiring
- Combustion and safety tests
- Gas line and vent connections
- The permit and the manufacturer warranty registration
- Removing and hauling away the old furnace
Missouri Permits, Efficiency Rules and Rebates
Missouri falls in the DOE's North region. New split central air conditioners must meet at least 13.4 SEER2, and heat pumps sold anywhere in the U.S. need 14.3 SEER2 and 7.5 HSPF2. Plan on a mechanical permit for most replacements in St. Louis; the contractor normally pulls it. Before you sign, ask each bidder for their Missouri license or registration number and proof of insurance. The federal 25C tax credit ended for equipment installed after December 31, 2025, so incentives now come mostly from utilities and state programs. Check your electric and gas utility's rebate page before you pick equipment.
Before You Hire
- Look up utility rebates on 95%+ AFUE units before you buy.
- Make sure all three quotes are for the same AFUE and staging, or you can't compare them.
- Replace it in early fall if you can. A no-heat emergency in January costs more and leaves you fewer choices.
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Furnace Replacement Questions from St. Louis Homeowners
How much is furnace replacement in St. Louis?
Plan on $3,000 to $7,300, with most jobs near $5,400. Equipment efficiency, house size and the condition of the ducts and wiring decide where your quote falls.
When is the best time to schedule furnace replacement in St. Louis?
Between late spring and early fall. St. Louis averages 79 freezing nights a year, and heating calls spike from November through February.
How long does a furnace replacement take?
A straight swap is usually done in one day, somewhere between 4 and 10 hours. Moving to a condensing furnace with new PVC venting can add a few more.
Is a high-efficiency furnace worth it?
In cold climates, a 95%+ AFUE furnace usually earns back the price difference in lower gas bills. Where winters are mild, the payback can take a very long time.
Furnace Replacement Near St. Louis
- Kansas City $3,200 to $7,900
- Springfield $2,900 to $7,000
- Columbia $3,300 to $8,000
- Independence $3,100 to $7,600
Sources: U.S. Census Bureau ACS 5-year estimates 2019-2023 and 2024 population estimates; NOAA NCEI U.S. Climate Normals 1991-2020, station St. Louis Sci Center; NOAA Storm Events Database 2020-2025, St. Louis city. Prices are our estimates, not contractor quotes. Updated 2026.