A St. Louis heat pump quote is a stack of decisions wearing a single number, and this guide unstacks it. The metro's price bands run from a few thousand dollars for a single-zone ductless unit in a South City flat to the deep five figures for a whole-home conversion in a Ladue colonial, and the spread between honest quotes for the same house is usually explained by scope rather than greed. What follows are the bands, the variables that move a project between them, where Ameren Missouri's FastTrack money belongs in the arithmetic, and the one discipline that keeps a five-figure decision from being graded by a single-digit January night it was never sized for.
The Bands
| Project type | Typical St. Louis range |
|---|---|
| Single-zone ductless | $4,000 to $7,500 |
| Multi-zone ductless, two to four heads | $9,000 to $18,000 |
| Ducted changeout, usable ducts | $9,000 to $16,000 |
| Whole-home conversion, new or heavy ductwork | $15,000 to $28,000 |
| Dual fuel, heat pump plus gas furnace | $12,000 to $22,000 |
The bands are wide because the houses are. A postwar Kirkwood ranch with clean trunks sits at the bottom of the changeout band; a Soulard rowhouse asking for four heads and line sets routed through brick sits high in the multi-zone band for reasons a site visit makes obvious. Treat any figure quoted before a measurement as a genre of fiction.
What the Climate Adds, and Does Not
St. Louis's design nights sit in the single digits, cold enough to demand the capacity-at-temperature check in our cold-weather guide but mild enough that many quality variable-speed machines qualify without the top-shelf cold-climate premium the northern tier pays. That widens the field and sharpens competition. What the climate does add is a second season: the machine must also be an excellent air conditioner, because a St. Louis August works it as hard as January does, and the variable-speed class that wins the winter question is the class that dehumidifies properly in summer. You are buying two seasons with one specification, which is the quiet economic argument for spending well once.
Where the Rebate Belongs
Ameren Missouri's FastTrack PAYS pathway pays up to $2,000 per qualifying air-source heat pump while funding lasts, per our rebates guide, and its correct position in the arithmetic is last. Price the project to stand on its own numbers first; then subtract a rebate whose availability was confirmed before signing and whose amount appears as a named line on the quote. A bid that leans on the rebate to make a bad price tolerable has the order backwards, and a bid citing the federal credits that ended December 31, 2025 is stale on its face. The claiming mechanics live on our Ameren Missouri page.
The Panel Question
Much of the metro's prewar stock, Soulard, Lafayette Square, Tower Grove, The Hill, the Central West End, and plenty of University City, runs 100 amp service, and a whole-home conversion can force new circuits or a service upgrade with Ameren coordination and lead time attached. Panel work runs roughly $1,500 to $4,000 when needed, and the honest bidder opens the panel at the site visit and prices what they find. The evasive one discovers it after signing, as a change order. Ask in the first call: what will you check on my panel, and will any panel work be itemized?
Ducts, Measured or Routed
The early-suburban rings, Kirkwood, Webster Groves, Clayton, carry real ducts with real quirks: trunks sized for a furnace's hot, fast air can choke a heat pump's steadier flow, and undersized returns complain in July as loudly as January. A static-pressure reading before sizing costs little and prevents the most common comfort complaint in the changeout band. In the brick stock, the question changes shape: usable ducts thin out, and the cost driver becomes head placement and line-set routing through masonry, decided by someone who can point to rowhouse work they have done. Both answers belong in writing before a price does.
Dual Fuel, the Metro's Middle Path
Greater St. Louis heats mostly on Spire gas, and for a household with a functioning furnace the dual-fuel configuration, a heat pump carrying the season with the furnace held for the deepest snaps, is a legitimate design a good contractor prices without being asked. It costs more than a straight changeout and less than ripping out working equipment, and the honest framing lives in our fuel comparison: gas is cheap heat here, and the conversion cases that clear are usually calendar cases, the furnace or the air conditioner at end of life.
The Cheaper Levers First
Two line items routinely outperform an extra ton of capacity per dollar. Air sealing and attic insulation shrink the load the machine must cover, sometimes enough to drop a size class, and in the metro's leaky brick and balloon-framed stock the effect is largest. A contractor who suggests envelope work before upsizing equipment is optimizing your money; one who solves every load with tonnage is optimizing their invoice.
Operating Cost, the Second Price
The purchase price is the number on the quote; the operating price arrives monthly for fifteen years. A properly sized variable-speed machine at St. Louis rates undercuts propane, oil, and resistance heat decisively and races Spire gas closely, with the full arithmetic in our fuel comparison. The sizing is what keeps the operating price honest: a machine leaning on electric resistance backup through every cold snap pays full resistance rates at exactly the hours the load peaks.
Three Quotes, Read Correctly
Collect three bids and expect the market to sort itself. One arrives fast, low, and paperless; it has skipped the load calculation and its price is an estimate of your patience. One arrives high and thorough; make it justify its scope line by line, which a good contractor does without flinching. The signable bid usually produced documents before being asked: a room-by-room load calculation, published capacity at the design condition, the FastTrack line named with availability confirmed, panel and duct findings in writing. The vetting sequence lives in our contractor guide. Price matters, but only between bids that passed.
The Short Version
Single-zone ductless from about $4,000; whole-home conversions to the high twenties; the brick stock pays a routing premium and the suburban rings pay for duct corrections when the measurement demands them. FastTrack's $2,000 comes off the end of arithmetic that already cleared, while funding lasts and confirmed before signing. The climate charges for two seasons and pays back in the same currency. Spend the extra afternoon on the load calculation; it is the cheapest component in the entire project.
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