HVAC · St. Louis, MO
How much does furnace replacement cost in St. Louis, MO? (2026)
In St. Louis, furnace replacement runs $3,950–$7,100, with most paying around $5,550 — about 3% above the national average. Replacing a residential furnace, including the unit and installation labor.
Updated June 2026 · Localized estimate, not a quote
Most homeowners pay around $5,550
- Typical cost
- $5,550
- Labor vs US
- −3%
- Climate
- Mixed
- Local permit
- $225
Refine your estimate
Tune it to your home to narrow the furnace replacement range.
Key takeaways for St. Louis
- Most St. Louis homeowners land around $5,550 for furnace replacement, within a $3,950–$7,100 range that sits about 3% above the national average.
- Running −3% against the US average, St. Louis labor is what moves this price off the national figure.
- Set aside roughly $225 for the permit; that's already part of the range above, not an add-on.
- 15 to 30 years is the usual service life, so budget for the next one before it fails.
- Booking during Spring and fall (Mar–May, Sep–Oct) typically saves about 5–15% versus peak-season pricing.
- Federal 25C/25D credits plus utility rebates sit below and can shave the final bill; the estimate here is pre-incentive.
What goes into the price in St. Louis
A typical St. Louis furnace replacement of $5,550 breaks down roughly like this — materials priced near the national level, labor set by local rates.
| Line item | St. Louis 2026 range |
|---|---|
| Materials & equipmentUnit, materials and supplies — priced close to the national level. | $1,500 – $2,750 |
| Labor & installationCrew time for removal, installation and startup; local labor rates drive most of the swing here. | $2,225 – $4,125 |
| Permit & feesLocal building-department fee for HVAC work here. | $225 |
| Total installed cost | $3,950 – $7,100 |
Split from the St. Louis estimate using a 60% local-labor share; line items sum to the total.
Why furnace replacement costs what it does in St. Louis
- Expect labor here to run 3% below the national norm (based on price levels for the St. Louis metro area) — that's what lowers the total.
- A HVAC permit in St. Louis costs around $225, included above.
Furnace Replacement cost by home size in St. Louis
Furnace cost scales with the heating capacity (BTU) your home needs — roughly 40–45 BTU per square foot in a mixed climate. Larger homes need a bigger unit and more ductwork.
| home size | St. Louis 2026 range |
|---|---|
| 1,000 sq ft (≈45,000 BTU) | $2,950 – $5,350 |
| 1,500 sq ft (≈68,000 BTU) | $3,450 – $6,100 |
| 2,000 sq ft (≈90,000 BTU) | $3,950 – $7,100 |
| 2,500 sq ft (≈110,000 BTU) | $4,550 – $8,100 |
| 3,000 sq ft (≈130,000 BTU) | $5,150 – $9,050 |
| 3,500+ sq ft (≈150,000 BTU) | $5,700 – $10,050 |
National size ranges localized to St. Louis labor and climate.
Furnace Replacement cost by type in St. Louis
| Gas furnace | $3,850 – $7,000 |
| High-efficiency gas furnace | $3,450 – $7,000 |
| Electric furnace | $2,200 – $4,650 |
Adjusted to St. Louis from national type-level ranges.
Furnace Replacement cost by efficiency in St. Louis
Efficiency is measured in AFUE — the percentage of fuel turned into heat. Higher AFUE costs more upfront but cuts fuel bills, and in cold (northern) regions the DOE requires ≥95% AFUE gas furnaces.
| 80% AFUE (standard)Lowest upfront; fine in mild climates | $3,150 – $5,650 |
| 90–95% AFUE (high-efficiency)Best all-round value in most regions | $3,950 – $7,100 |
| 96%+ AFUE (condensing, premium)Lowest fuel bills; required in cold zones | $5,150 – $9,550 |
Labor vs. materials in St. Louis
Install crew, removal, permit & startup — the part St. Louis rates move most.
Equipment & materials — priced closer to the national level.
Split based on a typical $5,550 St. Louis project; your mix varies with scope.
How we estimate it
| National range | $3,800 – $7,000 |
| St. Louis labor adjustment | ×0.98 |
| mixed climate factor | ×1 |
| Local permit | +$225 |
| St. Louis estimate | $3,950 – $7,100 |
Promo prices vs. the real cost
HVAC advertising runs on two numbers: the one that gets a tech to your door and the one that finishes the job. Here's what the door-opener figure usually accounts for:
- Service call / diagnostic fee$75–$150
- Seasonal tune-up promo$79–$129
- Financing offers$0 down · 0% APR, 12–60 mo
- "Free" replacement estimate$0 — it's a sales visit
Additional furnace replacement costs to budget for
Treat them as possibilities, not certainties — the ones that reach your quote follow your property's age and setup.
| Old furnace removal & disposal | $50 – $330 |
| New ductwork (vs. repair $300–$1,500)Only if ducts are missing or failing | $1,000 – $5,000 |
| Gas line run or upgrade | $250 – $800 |
| Chimney liner (for high-efficiency venting) | $600 – $2,500 |
| Smart thermostat | $150 – $500 |
Typical national add-on ranges; confirm locally during your quote.
What's included
- Removal and disposal of the old unit
- Thermostat connection and system startup/testing
- The furnace unit and burner assembly
- Installation labor and basic ductwork connections
What affects the cost
- Condition of existing ductwork and venting
- Fuel type (gas vs electric) and AFUE efficiency rating
- Heating capacity (BTU) needed for your square footage
- Whether a chimney liner or new gas line is required
Ways to save on furnace replacement in St. Louis
- Schedule in the off-season (spring/summer) for better rates
- Look for utility rebates on high-efficiency models
- Get at least 3 quotes — installed prices vary widely
- Right-size the unit; oversizing wastes money and cycles hard
How long does furnace replacement last in St. Louis?
Gas furnaces typically last 15–20 years; well-maintained units can reach 30.
An annual tune-up keeps efficiency up and protects the warranty.
Signs you need furnace replacement in St. Louis
- The furnace is 15+ years old (near or past its service life)
- Heating bills keep climbing despite no change in usage
- Some rooms are warm while others stay cold (uneven heating)
- Frequent repairs — you've called for service more than once or twice recently
- Banging, rattling or screeching noises on startup
- A yellow or flickering burner flame instead of steady blue (have it checked immediately)
- More dust, dryness, or a stale smell when the heat runs
Repair or replace in St. Louis?
Repair if…
- The unit is under ~10 years old and otherwise efficient
- The fix is a single inexpensive part (igniter, flame sensor, capacitor)
- It's still under manufacturer warranty
Replace if…
- It's 15+ years old and needs a major part
- The heat exchanger is cracked (a safety issue — replace, don't repair)
- The repair costs more than about half of a new system
- It's an 80% AFUE unit and your fuel bills are high in a cold climate
Rebates & incentives in Missouri
Most 2026 rebates reward switching to a heat pump, not a like-for-like gas furnace. Replacing a gas furnace, your savings are mainly utility efficiency rebates (high-AFUE models) — but pricing out a heat pump often qualifies you for far larger rebates.
The federal 25C tax credit (up to $2,000 for heat pumps; $600 for high-efficiency AC or furnaces) and the 25D credit ended December 31, 2025 under the One Big Beautiful Bill Act — neither is available for 2026 installs. The remaining federal help is the IRA Home Electrification & Appliance Rebates (HEAR): up to $8,000 toward a heat pump for households under 150% of area median income, paid at point of sale where a state has launched its program.
Verified July 2026. Rebate budgets deplete and program windows change fast — confirm current amounts and eligibility with your utility and the DSIRE database before you budget. Costadia does not administer these programs.
Cheapest time for furnace replacement in St. Louis
A furnace or AC that dies mid-heat-wave gets replaced at whatever the on-call crew charges. One that gets swapped in April or October gets a competitive, unhurried quote instead.
Why furnace replacement quotes vary — and how to compare them fairly
Big gaps between bids come down to scope far more often than greed. This breaks down the levers and how to force a like-for-like comparison.
Why a quote looks high (or low)
- One quote bundles ductwork, electrical, permit and old-unit removal; another quietly leaves them out.
- Brand, warranty length and whether startup/commissioning is included all move the number.
- Sizing was guessed from square footage instead of a Manual J load calculation, so the equipment is wrong.
Get an apples-to-apples bid
- Ask every bidder for the same SEER2/AFUE rating so you compare like for like.
- Confirm old-unit removal, the permit and startup testing are all included.
- Insist on a Manual J load calculation, not a square-footage guess.
- Require an itemized quote splitting equipment, labor, permit and add-ons.
Questions to ask St. Louis HVAC pros
The only honest way to compare is to hold every quote to one checklist. Start with these.
- 1Did you run a Manual J load calculation to size the system, or estimate from square footage?
- 2What AFUE/SEER2 rating is this unit, and what's the payback vs. the next tier up?
- 3Is removal of the old equipment, the permit, and startup testing included in the quote?
- 4Will my existing ductwork and venting work as-is, or is repair/resizing needed?
- 5What's covered under the labor warranty vs. the manufacturer's parts warranty?
Furnace Replacement in St. Louis
How much does furnace replacement cost in St. Louis, MO?
St. Louis's going rate for furnace replacement is $3,950–$7,100 in 2026, with $5,550 the number most homeowners end up paying. St. Louis labor rates, the mixed climate and permit fees each shift the total, and all three already sit inside this range.
Is furnace replacement more expensive in St. Louis than average?
Yes — St. Louis is about 3% higher than the national average, largely a function of local labor pricing at 0.98× the US average., plus a local HVAC permit running about $225.
Do I need a permit for furnace replacement in St. Louis?
Do you need a permit? For this work in St. Louis, yes — a HVAC permit at roughly $225, and the estimate above already carries it.
What affects furnace replacement cost the most?
Replacing a residential furnace, including the unit and installation labor. Where two homes diverge is in the details below. Expect equipment/material grade, home size and complexity, local labor rates and the mixed climate zone to matter most here.
How much should you really budget for HVAC in 2026?
Sizing, efficiency tier and brand pull a quote in different directions. Here's how our editors weigh the trade-offs that decide what you actually pay.
The budget-first case
Run a Manual J load calculation, then buy the standard tier — 80% AFUE, 14.3 SEER2 — and stop there. Where summers are short and winters are gentle, the equipment idles most of the year, so premium efficiency never gets enough runtime to earn back its price. Paying for SEER2 you'll rarely tap is the classic way a mild-climate homeowner overspends.
The longevity case
The single biggest cost driver isn't the brand — it's correct sizing and install quality. A properly sized, well-commissioned mid-tier system with annual maintenance outlasts an oversized premium unit that short-cycles. Spend on the install, not the badge.
The efficiency-first case
High runtime changes the math. In a demanding climate the extra efficiency of a heat pump or a top-tier SEER2/AFUE unit gets paid back month after month on the utility bill, and state and utility incentives can shave the upfront figure further now that the federal 25C/25D credits have expired. Price the lifetime bills, not just the tag, before you default down.
Get the sizing and the commissioning right and the brand debate mostly disappears. Insist on a Manual J, pick an efficiency tier your climate can justify, and pocket every incentive that still applies after the federal credits lapsed.
Editorial analysis by Serhat Özçelik, reviewed by Costadia Editorial. These are our own cost perspectives, not third-party endorsements.
How we calculated this estimate
We start with 2026 national furnace replacement ranges compiled from contractor-pricing sources (Angi, HomeGuide, Fixr and EnergySage averages), then localize them to St. Louis using the BEA Regional Price Parity labor index (×0.98 here), the IECC mixed-climate factor (×1) and a typical local permit fee (≈$225). Federal incentive details reference the IRS Inflation Reduction Act (25C/25D) and DSIRE.
This is a planning estimate, not a quote.Actual prices vary with your home's condition, equipment grade and contractor — always confirm with licensed local pros before budgeting.
References & data sources
Our St. Louis furnace replacement estimate is built from these primary, mostly government sources — not a single aggregator.
- Occupational Employment & Wage Statistics (metro wages) — U.S. Bureau of Labor Statistics.Metro-level trade wages behind each city's labor index.
- Regional Price Parities (state & metro) — U.S. Bureau of Economic Analysis.Regional price levels used where metro wage data is unavailable.
- IECC Climate Zones — U.S. DOE — Building Energy Codes Program.Climate-zone factors applied to weather-sensitive projects.
- Home Energy Tax Credits (25C / 25D) — Internal Revenue Service.Federal rebate and tax-credit figures for eligible upgrades.
- Database of State Incentives for Renewables & Efficiency — DSIRE — NC State University.State and utility incentive programs by ZIP code.
Furnace replacement alternatives in St. Louis
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