How much does HVAC cost in St. Louis?
By Our research team · Last verified · Methodology
Most St. Louis homeowners pay $3,800–$8,550 to replace a central AC of 3 tons on existing ducts, with $5,900 typical. Gas furnaces run $2,700–$7,750 and heat pumps $5,300–$12,100.
How we get this data- Typical
- $5,900
- Low end
- $2,850
- High end
- $12,850
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St. Louis's price band
St. Louis is pricier than 65% of the 195 US metros we price for HVAC work.
Replacing a 3-ton central AC in St. Louis costs $3,800–$8,550 on existing ducts, with $5,900 typical. A 3-ton heat pump runs $5,300–$12,100, a gas furnace $2,700–$7,750, and a single-zone mini-split $2,400–$5,400.
St. Louis has hot, humid summers and cold winters, so gas furnace + AC is the default and the two are often replaced together. Many older brick homes have small ducts, which can limit how large a system fits.
These are installed prices for St. Louis, re-verified in November 2026. Removal and startup are normally included; the permit, a new line set and duct repairs often are not. Get them itemized.
Comparing cities, or after the US-wide picture? See the national guide: HVAC cost in the USA.
$3,800–$8,550 to replace a 3-ton central AC on existing ducts in St. Louis, installed — $5,900 typical. A heat pump runs $5,300–$12,100, a gas furnace $2,700–$7,750, and AC + furnace together $6,300–$15,450. Verified November 2026. Get free St. Louis quotes →
- 3-ton central AC on existing ducts: $3,800–$8,550 ($5,900 typical)
- Heat pump, 3-ton: $5,300–$12,100; gas furnace: $2,700–$7,750
- AC + furnace together: $6,300–$15,450
- Mini-split: $2,400–$5,400 for one 12,000 BTU zone, $7,750–$17,400 for four
- Downtown, Grand Center & the Grove runs 5–10% above the city average; South City & Dutchtown: standard pricing
Prices verified November 2026 · Cross-referenced against 45+ American pricing sources · See methodology
Installed prices for the St. Louis metro, re-verified November 2026. Equipment-heavy jobs move less with local labor costs than service calls do.
| Service | Low | Typical | High |
|---|---|---|---|
| Central AC replacement, 3-ton (existing ducts)installed | $3,800installed | $5,900 | $8,550 |
| Central AC + gas furnace, replaced togetherinstalled | $6,300installed | $9,450 | $15,450 |
| Heat pump replacement, 3-ton (existing ducts)installed | $5,300installed | $7,750 | $12,100 |
| Central heat pump, high-efficiency with zoning (3-ton)installed | $9,650installed | $14,000 | $20,300 |
| Gas furnace replacement (80–96% AFUE)installed | $2,700installed | $4,450 | $7,750 |
| Ductless mini-split, 1 zone, 9,000 BTUinstalled | $2,150installed | $3,200 | $4,650 |
| Ductless mini-split, 1 zone, 12,000 BTUinstalled | $2,400installed | $3,750 | $5,400 |
| Ductless mini-split, 1 zone, 18,000 BTUinstalled | $3,100installed | $4,850 | $6,950 |
| Ductless mini-split, 1 zone, 24,000 BTUinstalled | $3,650installed | $6,000 | $8,500 |
| Ductless mini-split, 1 zone, 30,000–36,000 BTUinstalled | $4,650installed | $7,550 | $11,100 |
| Multi-zone mini-split, 2 zonesinstalled | $4,350installed | $6,300 | $9,650 |
| Multi-zone mini-split, 4 zonesinstalled | $7,750installed | $11,600 | $17,400 |
| Like-for-like AC swap: same-size mini-split, existing line setinstalled | $2,200installed | $3,400 | $5,000 |
| Install only: homeowner-supplied mini-split, 1 zonelabor only | $480labor only | $1,050 | $1,900 |
| Evaporative (swamp) cooler, roof-mountedinstalled | $1,250installed | $2,200 | $3,500 |
| Ductwork replacement, whole houseinstalled | $2,400installed | $5,300 | $9,150 |
| AC compressor replacement (out of warranty)per repair | $1,250per repair | $2,050 | $2,900 |
| AC repair, major: refrigerant leak fix + rechargeper repair | $580per repair | $1,250 | $2,400 |
| AC repair, minor: capacitor, contactor or drain lineper repair | $140per repair | $290 | $570 |
| AC tune-upper visit | $70per visit | $100 | $190 |
| Whole-system HVAC tune-up (AC + furnace)per year | $140per year | $220 | $430 |
| Duct cleaning, whole houseper home | $290per home | $430 | $670 |
| Smart thermostat, installedinstalled | $200installed | $290 | $440 |
| Old AC or furnace removal and disposalper unit | $95per unit | $240 | $480 |
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Prices verified November 2026 · Cross-referenced against 45+ American pricing sources · See methodology
Figures are for the St. Louis metro area in November 2026. Rural edges may add trip fees; Downtown, Grand Center & the Grove sits at the top of these ranges.
HVAC prices across St. Louis
Where you live changes the quote. Downtown, Grand Center & the Grove costs the most because of access and older buildings; South City & Dutchtown usually comes in at or under the city typical.
Downtown, Grand Center & the Grove
- Installed
- $4,000–$9,400 installed
- Typical job
- $5,600–$7,450 / 3-ton AC swap
The priciest part of the metro for a swap: roof access, cramped closets for air handlers and limited parking stretch a one-day job. Many older units here have no ducts at all.
North St. Louis
- Installed
- $3,900–$9,000 installed
- Typical job
- $5,400–$7,100 / 3-ton AC swap
Renovated older homes. Contractors here often find leaky ducts or a tired air handler or furnace, which is where a simple AC quote grows.
South City & Dutchtown
- Installed
- $3,800–$8,550 installed
- Typical job
- $5,300–$6,800 / 3-ton AC swap
Mostly houses with central systems in garages, closets, attics or basements. Quotes cluster around the city typical.
St. Charles, Clayton & the suburbs
- Installed
- $3,800–$9,050 installed
- Typical job
- $5,300–$7,200 / 3-ton AC swap
Larger homes on easy lots. The ton count drives the price more than access, and two-system homes are common.
Real-world HVAC costs in St. Louis
Here's what common HVAC jobs cost in St. Louis in 2026, a 3-ton central AC replacement on existing ducts, installed.
Swap a 3-ton AC on good ducts
Same spot, same size, matched indoor coil, old unit hauled away. Most St. Louis jobs land near $5,900; a 17+ SEER2 unit adds about $2,000.
Replace the AC and gas furnace together
The usual move when both are 15+ years old. One install, one warranty, a matched system. Typical is $9,450.
Switch from AC + furnace to a heat pump
A 3-ton heat pump on existing ducts, typically $7,750. Keeping the furnace as backup (dual-fuel) runs $6,850–$16,400.
Cool one room with a mini-split
A 12,000 BTU single-zone mini-split for a bedroom, office or addition, typically $3,750. A 9,000 BTU unit for a small room is $2,150–$4,650.
Cool a whole home with no ducts
A 4-zone ductless system, typically $11,600. Adding ducts for central AC instead costs $2,400–$9,150 before the equipment.
How much does HVAC cost in St. Louis?
A typical 3-ton replacement in St. Louis is $5,900, inside a normal range of $3,800–$8,550. That price is about 5% below the US typical of $6,200. Most of the difference between quotes is efficiency, brand and how hard the old equipment is to reach.
For homes without ducts, a single-zone mini-split runs $2,400–$5,400 and a 4-zone system $7,750–$17,400. Adding whole-house ducts instead costs $2,400–$9,150 on top of the equipment.
Central AC, heat pump and furnace prices in St. Louis (2026)
A 3-ton central AC runs $3,800–$8,550, a 3-ton heat pump $5,300–$12,100, and a gas furnace $2,700–$7,750, all installed.
| Line on the quote | Low | Typical | High |
|---|---|---|---|
| Central AC replacement, 3-ton (existing ducts) | $3,800 | $5,900 | $8,550 |
| Heat pump, 3-ton (existing ducts) | $5,300 | $7,750 | $12,100 |
| Gas furnace (80–96% AFUE) | $2,700 | $4,450 | $7,750 |
| Central AC + gas furnace together | $6,300 | $9,450 | $15,450 |
| Mini-split, 1 zone, 12,000 BTU | $2,400 | $3,750 | $5,400 |
| Mini-split, 2 zones | $4,350 | $6,300 | $9,650 |
| Mini-split, 4 zones | $7,750 | $11,600 | $17,400 |
| Ductwork replacement, whole house | $2,400 | $5,300 | $9,150 |
The gap between an AC and a heat pump in St. Louis is about $1,850 at the typical price. That gap buys heating as well as cooling, so it matters most when the furnace is near the end of its life.
What moves an HVAC quote in St. Louis:
- Size: a 2-ton system runs about $4,950 and a 5-ton about $8,300 at the typical price. Ask for a Manual J load calculation.
- Efficiency: the minimum here is 13.4 SEER2; a 17+ SEER2 two-stage unit adds about $2,000.
- Access: attic air handlers, rooftop condensers and tight closets add labor, most often in Downtown, Grand Center & the Grove.
- Line set and coil: a new line set runs $190–$620, and the indoor coil has to match the new refrigerant.
- Season: spring and fall bring the best prices; a breakdown during a summer heat wave brings the worst.
Ask every St. Louis contractor for the same things: tonnage, SEER2 rating, model numbers for both the outdoor and indoor units, and whether the permit and line set are included. Compare those, not just the total. Get a quote for your heating and cooling work →
HVAC cost in St. Louis by home size
About $5,350 for a 2.5-ton AC (1,000–1,600 sq ft), $5,900 for 3 tons (1,600–2,000 sq ft), and $7,300–$8,300 for 4–5 tons in homes over 2,500 sq ft, typical St. Louis prices on existing ducts.
Worked example: a 2,000 sq ft St. Louis home with a 16-year-old AC and furnace. Replacing both runs about $9,450; switching to a 3-ton heat pump on the same ducts runs about $7,750; replacing only the AC is $5,900 but leaves an old furnace in place.
Homes over 2,500 sq ft or with two floors often have two systems or zoning. A high-efficiency zoned heat pump runs $9,650–$20,300, and adding zoning to an existing system $1,650–$4,350.
St. Louis HVAC costs by system type
| System type | Cost | Best for |
|---|---|---|
| Central AC, 3-ton (existing ducts) | $3,800–$8,550 installed | Homes with sound ducts and a furnace or air handler to pair with |
| Ductless mini-split, single zone (9,000–18,000 BTU) | $2,150–$6,950 installed | One room, an addition, or a home with no ducts |
| Multi-zone ductless mini-split (2–4 zones) | $4,350–$17,400 installed | Whole homes with no ducts, room-by-room control |
| Heat pump, 3-ton ducted (heats and cools) | $5,300–$12,100 installed | Mild and hot climates; replacing an AC and electric heat |
| Gas furnace + AC, replaced together | $6,300–$15,450 installed | Cold climates with natural gas and old equipment on both sides |
| Gas furnace only (80–96% AFUE) | $2,700–$7,750 installed | When the AC is newer than the furnace |
| Dual-fuel: heat pump + gas furnace | $6,850–$16,400 installed | Cold climates: electric heat most days, gas on the coldest |
| Cold-climate heat pump, 3-ton ducted | $9,200–$23,200 installed | Northern homes leaving gas, oil or propane |
| Central heat pump, high-efficiency with zoning | $9,650–$20,300 installed | Big or two-story homes with hot and cold rooms |
| Evaporative (swamp) cooler, roof-mounted | $1,250–$3,500 installed | Dry Western climates only |
| Geothermal heat pump (ground loop) | $14,500–$33,800 installed | Large lots and long stays in one home |
| Window or through-the-wall AC | $200–$1,150 installed | Single rooms and renters; cheapest way to cool |
Equipment vs installation: the St. Louis AC bill
On a typical $5,900 3-ton swap in St. Louis, the condenser and matched coil are roughly $2,350–$3,550 and the rest is labor, materials, the permit and overhead. Labor usually makes up 40–60% of an AC replacement.
Buying the unit yourself rarely saves much: many contractors won't install customer-supplied equipment, and the ones who do charge $480–$1,900 or more for a mini-split and won't cover the parts. Brand warranties often require a licensed installer.
What's included in a St. Louis AC replacement (and what costs extra)
A standard replacement quote covers the outdoor unit, a matched indoor coil, refrigerant, connection to your existing ducts and wiring, removal of the old unit, and startup. Common extras:
- Permit and inspection: $95–$240, often built into the quote
- New refrigerant line set: $190–$620 if the old one can't be reused
- New condenser pad: $40–$240
- Electrical panel upgrade: $810–$3,850, mostly when adding a heat pump or more capacity
Ask for the AHRI certificate showing the matched rating of your outdoor and indoor units. It proves the system you paid for is the one that was installed.
St. Louis's climate
St. Louis has hot, humid summers and cold winters, so gas furnace + AC is the default and the two are often replaced together. Many older brick homes have small ducts, which can limit how large a system fits.
System size
Each ton adds equipment cost: about $4,950 for 2 tons and $7,300 for 4 tons at the typical St. Louis price. A Manual J load calculation often shows a smaller system will do.
Efficiency rating
The federal minimum for a new split AC here is 13.4 SEER2. Higher ratings cost more upfront and pay back fastest where AC runs most of the year.
New refrigerants
New systems use A2L refrigerants (R-454B or R-32), so the indoor coil must match the outdoor unit. That's why condenser-only swaps are rare now, and why older R-410A systems cost more to service.
Ducts and access
Leaky or undersized ducts, attic air handlers and rooftop condensers add hours. Whole-house duct replacement runs $2,400–$9,150.
Location: Downtown, Grand Center & the Grove vs South City & Dutchtown
Downtown, Grand Center & the Grove jobs cost more because of access, parking and older buildings. South City & Dutchtown quotes usually sit at or a little under the city typical.
Season and urgency
Replacing on your schedule in spring or fall is cheaper than an emergency swap in a heat wave. After-hours repair labor runs $150–$240 an hour.
- Get three quotes for the same system.Same tonnage, same SEER2 rating, model numbers on every quote. St. Louis quotes for the same 3-ton swap run anywhere from $3,800 to $8,550.
- Replace before it fails.If your system is 12–15+ years old, replace it in spring or fall. Emergency replacements in peak season leave no room to shop around.
- Right-size the system.Ask for a Manual J load calculation. An oversized AC costs more, cycles on and off, and leaves the house clammy.
- Check your utility for rebates.There is no federal tax credit for systems installed in 2026, but many utilities still pay rebates on efficient heat pumps and AC. Check before you sign; most require pre-approval or a listed contractor.
- Do the AC and furnace together if both are old.One install of both runs $6,300–$15,450, less than two separate jobs.
- Keep up with tune-ups.A yearly tune-up at $70–$190 catches weak capacitors and low refrigerant before they kill a compressor ($1,250–$2,900).
Before you pay a deposit to a St. Louis HVAC contractor, get these in writing:
- Tonnage and how it was sized (a Manual J load calculation)
- Model numbers for the outdoor unit and the indoor coil or air handler
- The matched SEER2 (and HSPF2 for a heat pump) rating
- Whether the line set is new, flushed or reused
- Permit, inspection and removal of the old unit
- Thermostat, pad, disconnect and any electrical work
- Parts and labor warranty terms, and who registers the equipment
- Total price, deposit, and start and finish dates
How much does it cost to replace a central AC in St. Louis?
$3,800–$8,550 for a 3-ton system on existing ducts, installed, with $5,900 typical in St. Louis. Higher-efficiency units, attic or rooftop installs and new line sets push it up.
How much does a heat pump cost in St. Louis?
$5,300–$12,100 for a 3-ton heat pump on existing ducts, about $7,750 typical. A high-efficiency zoned system runs $9,650–$20,300.
How much is a new furnace in St. Louis?
$2,700–$7,750 for a gas furnace installed, about $4,450 typical. With a new AC at the same time, $6,300–$15,450.
How much does a mini-split cost in St. Louis?
$2,400–$5,400 for a 12,000 BTU single zone, $4,350–$9,650 for two zones and $7,750–$17,400 for four.
How much is an AC tune-up in St. Louis?
$70–$190 per visit. A yearly plan for AC and furnace runs $140–$430.
How much does AC repair cost in St. Louis?
$140–$570 for common fixes like a capacitor or contactor. A refrigerant leak repair with recharge runs $580–$2,400, and a compressor $1,250–$2,900.
What size AC does a St. Louis home need?
As a rough guide, 2.5 tons covers about 1,000–1,600 sq ft and 3 tons about 1,600–2,000 sq ft, but insulation, windows and climate change that. Ask for a Manual J load calculation instead of matching the old unit.
Is there a tax credit for a new AC or heat pump in St. Louis?
No federal one for 2026: the 25C credit covered improvements made through December 31, 2025. Utility and state rebates may still apply, so check before you buy.
Do I need a permit to replace an AC in St. Louis?
Usually, yes. Most US cities and counties require a mechanical permit for an AC or furnace replacement, typically $95–$240, and a licensed contractor normally pulls it.
How much does it cost to add ducts in St. Louis?
$2,400–$9,150 for whole-house ductwork, before the AC or heat pump. In many older homes a multi-zone mini-split ($7,750–$17,400 for four zones) costs less.
Prices verified November 2026 · Cross-referenced against 45+ American pricing sources · See methodology
Prices for the St. Louis metro area, November 2026. Outer suburbs may vary.
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