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Heat pumps by metro · Missouri · Illinois · checked October 19, 2026
Heat pumps in St. Louis
Winters are cold enough that output in a cold snap matters, and summers need real cooling. At Missouri prices a cold-climate heat pump delivers heat for about $16.84 per million Btu, against $15.16 for a high-efficiency gas furnace.
What this means for your house: Both seasons count here: real winters and humid summers, so fixes should help heating and cooling.
Climate and sizing
Winters are cold enough that output in a cold snap matters, and summers need real cooling. This is a humid climate: a variable-speed system that runs longer at low speed pulls more moisture out of the air than a single-stage one. Whatever the climate, the system should be sized from a room-by-room load calculation (ACCA Manual J), not from
the size of the old air conditioner or furnace: an oversized heat pumpshort-cycles, dehumidifies poorly and costs more.
Degree days: NOAA1991–2020 climate normals. Climate zone: IECC 2021 (PNNL county list). Housing: Census American Community Survey.
Seasonal COP: Seasonal COP is the heat delivered over a whole heating season, including electric backup heat and defrost, for a heat pump sized for the house. We pick the planning value by how cold the winter is (heating degree days) and set it slightly below modelled results (Dunsky/CCI 2024), because measured field performance tends to come in lower. For your own house, the HSPF2 rating of the system you choose and your installer's Manual J load calculation are the better guide.
You pay to heat and to cool, and muggy summers make basements and AC health matter.
You pay to heat in winter and to cool and dry the air in muggy summers. Many homes are old, with basements that can get damp and lead paint to plan around. A good audit covers air sealing and attic insulation, basement moisture, safe venting of fuel-burning equipment and AC health.
What to look for in this climate
Federal AC rules differ here: Baltimore and DC follow Southeast rules (14.3 SEER2 for most split ACs), while New York, Philadelphia and St. Louis follow North rules (13.4 SEER2).
Split heat pumps must meet at least 14.3 SEER2 and 7.5 HSPF2. ENERGY STAR models start at 15.2 SEER2 and 7.8 HSPF2.
A cold-climate heat pump is optional, since winters rarely reach 0°F. Still check capacity at 17°F and 5°F for the coldest days.
Size with Manual J. An oversized AC short-cycles and leaves your house cool but clammy.
Do these alongside the new system
Air sealing plus attic insulation. It cuts both heating and cooling loads, and ENERGY STAR says sealing and insulating can save up to 10% on annual energy bills.
Basement water fixes, rim sealing, dehumidification. Controls summer basement humidity and mold, and closes a common air leak at the rim joists.
Duct sealing, or moving ducts inside. Where ducts run through an unconditioned attic, they can lose 10–45% of the heating and cooling energy they carry. Sealing, insulating or moving them inside cuts that loss.
Heat pumps, ducted or ductless. These cities average 0–1 nights a year at or below 0°F, so a standard variable-speed heat pump can carry most hours. Ductless units suit radiator homes.
Heat pump water heater in the basement. It cools and dehumidifies the space around it, which helps in a muggy basement.
Mistakes to avoid
An oversized AC. It cools fast but shuts off before removing moisture, so rooms feel clammy.
Heating and cooling both count here: winters are real, so the price of each unit of heat matters, but so does summer efficiency. Cost per million Btu of heat delivered into the house, at Missouri's average residential prices from the EIA (electricity for
July 2026, gas as an annual average). Here a heat pump needs a seasonal COP above 3.1 to beat a 95% gas furnace, so at these prices gas stays cheaper to run; the case for a heat pump rests on replacing the air conditioner, cutting emissions or a time-of-use rate.
Against electric resistance heat (baseboards or an electric furnace), even a standard heat pump cuts the heating bill by about 60%.
Prices: EIA electricity · EIA natural gas. Your own rate plan may differ, especially on a time-of-use or heat pump rate.
What cooling costs in St. Louis
Summer matters too. Air conditioning for a typical 1,600 sq ft single-family house with central air, at Missouri's average residential
electricity price (16.1¢ per kWh, EIA, July 2026). In this humid climate, part of the air conditioner's job is pulling moisture out of the air. A right-sized variable-speed system runs longer at low speed and removes more of it; an oversized one cools quickly, shuts off and leaves the house clammy.
Yearly cooling electricity and cost by system efficiency in St. Louis
Every heat pump program we found for the St. Louis area, with the equipment rule that decides which models qualify. Checked against each
program's own page on October 19, 2026. Most utility programs need an AHRI-matched system; check the exact pairing in the AHRI directory before you sign.
Ameren Missouri PAYS heating and cooling rebates
Closed now
Ameren Missouri
Heat pump amountsRebate sheet valid Jan. 1-Dec. 31, 2026, for PAYS tier 4 participants only. Air-source heat pump replacing an ASHP, replacing electric resistance, or where there is no existing central system: $2,000 per system. Dual-fuel ASHP: $2,000. Ground-source: $5,000. Mini-split A/C or heat pump: $500 per ton.
Equipment ruleASHP and dual fuel 15.2+ SEER2; GSHP 23+ EER; mini-split 19+ SEER2. 'A home with existing non-electric heat must maintain that heat source (as primary or backup)'; 'Ameren Missouri does not promote fuel switching or load building.' The customer must have lived in the home for the past 12 months. No sizing rule is stated.
Other conditionsContractors generate the offer through the FastTrack app; customers may select up to three contractors.
StatusClosed for 2026: 'Whole Home PAYS and FastTrack HVAC PAYS are no longer accepting enrollments for 2026'; 'The program has been fully subscribed for 2026.' No reopening date.
Ameren Illinois air-source heat pump instant discounts (Metro East)
Unconfirmed
Ameren Illinois
Heat pump amounts'You can receive an instant discount on ducted and ductless air source heat pumps from your local contractor'. No amounts are published on the page.
Equipment ruleThe page advises choosing 'an ENERGY STAR unit suited to your particular home'. It states no SEER2, HSPF2 or cold-climate rule.
Other conditionsDiscount through a local HVAC contractor; the page links a Program Ally finder but does not state it as a requirement.
StatusNo status stated; the page was last modified September 4, 2025, so its currency is uncertain
The federal rebate (formerly HEAR) pays up to $8,000 toward an ENERGY STAR certified heat pump for income-qualified households, through
the state. Since May 29, 2026 it covers only upgrades from existing electric equipment, and the installer must be on the state's
contractor list. Each state runs its own program; the status is in the list above.
Audit programs, other rebates and help for lower-income homes: our St. Louis guide.
Systems that suit St. Louis
The certified systems that heat most efficiently at 5°F, and those that cool most efficiently, on current refrigerants, from ENERGY STAR's US listings. Rebadged twins with identical ratings are folded into one row.
How to read the tables: SEER2 is cooling efficiency over a season and EER2 on the hottest afternoons; HSPF2 is heating efficiency over a
season, and COP at 5°F shows how efficiently the system still heats in deep cold. Size is the rated output in BTU/h (12,000 BTU/h is
one ton). The AHRI number identifies the exact certified pairing for rebates. Full definitions: how to read the numbers.
Central systems that heat best in the cold (2 tons and up)
Central systems that heat best in the cold (2 tons and up) for St. Louis
37MARAQ24AA3 45MAHAQ24XA3Same ratings also listed as Bryant, Midea, Heil, Tempstar, Comfortmaker, KeepRite and other ICP brands, Payne and WeatherMaker, Kenmore, LPS Legacy, Smart Comfort
BMS500-AAS024-1CSXRD BMS500-AAU024-1AHWXDSame ratings also listed as Midea, Moovair, Innovair, Stelpro, Dettson and Ouellet, Cooper & Hunter, ACiQ, Blueridge, AC PRO, CanAir
Tell us about your home and what you want to heat or cool. A person reads every request and replies with the contractors and rebate programs that serve your ZIP code.
