Do heat pumps work in St. Louis winters?

St. Louis sees about 29 nights a year at or below 20°F. A cold-climate certified model keeps the house warm without leaning on backup heat. The average winter low is 27°F, and the heating season adds up to 4,547 heating degree days (NOAA 1991-2020 normals).

How much does it cost to run a heat pump in St. Louis?

A typical 3-ton central heat pump (17.0 SEER2, 9.0 HSPF2) uses about $1,000 of electricity a year for heating and $309 for cooling in St. Louis, at the Missouri average of 13.9¢/kWh. The most efficient models cost less - see the rankings above.

Is a heat pump cheaper than a gas furnace in St. Louis?

Not on heating alone at today's prices: about $1,000 a year with a typical heat pump versus $982 with a 95% gas furnace (Missouri averages: 13.9¢/kWh, $1.44/therm). A high-HSPF2 model narrows the gap, and a heat pump also replaces the air conditioner. Against propane, oil or electric heat it is usually far cheaper.

What size heat pump do I need for a 2,000 sq ft house in St. Louis?

With average insulation, roughly a 4-ton system: the estimated cooling load is 30,600 BTU/h and the heating load 46,000 BTU/h. Use the size calculator for your own house, and ask installers for a Manual J calculation.

Cold winters · Warm summers

Best heat pumps for St. Louis, MO

St. Louis sees about 29 nights a year at or below 20°F. A cold-climate certified model keeps the house warm without leaning on backup heat.

A typical heat pump costs about $1,000 a year to heat a house here and $309 to cool it. A 95% gas furnace would cost $982 for the same heat.

Nights at or below 0°F1 a year
Nights at or below 20°F29 a year
Days at or above 90°F46 a year
Average winter low27°F
Average summer high88°F
Electricity13.9¢ per kWh
Natural gas$1.44 per therm

Cheapest to run in St. Louis

Ranked by yearly electricity cost in this climate, so the balance of heating and cooling efficiency is the one that matters here. Cold-climate certified models only.

Best 12,000 BTU mini-split

MDV MOX430-12HFN1-MZ60W

12,000 BTU mini-split · MSOP series · cold-climate certified

SEER2: 27.5
HSPF2: 14.5
Per year here: $271

For one large room.

Full specs and running cost

Best 24,000 BTU mini-split

SLIMAIR SHC24VH2AG

24,000 BTU mini-split · SHC Series · cold-climate certified

SEER2: 27.5
HSPF2: 14.5
Per year here: $541

For open-plan floor or small home.

Full specs and running cost

Best 3-ton central heat pump

TOSHIBA CARRIER MCY-MUB0368HS2P-UL

3 ton central · cold-climate certified

SEER2: 29.7
HSPF2: 12.2
Per year here: $915

For typical whole house.

Full specs and running cost

Running cost calculator for St. Louis

Pre-filled with St. Louis's climate and Missouri prices. Pick a model, tell it what you heat with today, and add your quote.

Heat pump $842/yrYou save $286/yrSee details ↓

1. Where you live

StateCityElectricity ¢ per kWh

Adjust heating and cooling hours

Filled in from your city's climate. Change them if you run the system much more or less than usual.

Cooling hours full-load hours per yearHeating hours full-load hours per year

2. The heat pump pick a model or type its ratings

Find a model (fills in the ratings below)

SEER2 cooling efficiencyHSPF2 heating efficiencyCooling capacity BTU/hHeating capacity BTU/h

3. What it replaces

Current heatingFurnace efficiency (AFUE %)Gas price, $/thermCurrent coolingOld AC rating SEER2 (10 ≈ 15+ years old)

4. Price replace the example with your quote

Installed price, $Rebates and incentives, $ utility, state

Heat pump, per year: $842
Current system, per year: $1,128
You save per year: $286
Payback: Over 30 years
Net after 10 years: -$6,141

Cooling $175Heating $667Electricity used: 6,060 kWhSaved vs. a minimum-efficiency heat pump: $203

Estimates use the unit's rated SEER2 and HSPF2, full-load hours derived from NOAA 1991-2020 degree days, average residential electricity prices from the U.S. EIA (12 months to July 2026) and fuel prices from EIA (2025 for natural gas, week of 2026-10-05 for propane and heating oil). Very cold days that need backup heat are not modelled. Federal minimum for comparison: 14.3 SEER2 / 7.5 HSPF2.

More for St. Louis

Top 5 12,000 BTU mini-splitsfrom $271/yr

Model	SEER2	HSPF2	Per year
MDV MOX430-12HFN1-MZ60W	27.5	14.5	$271
Goodman MSH123G26MCAA	27.5	14.5	$271
Fujitsu AOUH12KTAP1	31.5	13.7	$275
Fujitsu AOUG12LZAS1	29.4	12.9	$292
Fujitsu AOUH12KZAH1	30.5	12.7	$294

All 12,000 BTU mini-splits

Top 5 24,000 BTU mini-splitsfrom $541/yr

Model	SEER2	HSPF2	Per year
SLIMAIR SHC24VH2AG	27.5	14.5	$541
MDV MOD30-24HFN10-M1X	22.3	13.5	$601
Mainline ML24HP230NEXH-O	22.3	13.3	$608
ComfortStar CHF3-24CD(O)	22.3	13.3	$608
Arcoaire D5CSHAH24AAK	21.2	13.5	$610

All 24,000 BTU mini-splits

Top 5 3-ton central heat pumpsfrom $915/yr

Model	SEER2	HSPF2	Per year
TOSHIBA CARRIER MCY-MUB0368HS2P-UL	29.7	12.2	$915
LG KUSXA361A	23.5	10.5	$1,081
Trane 5TWV0X36A1	21.0	10.5	$1,107
LG KUSXB361A	22.0	10.3	$1,113
Lennox SL22KLV-036-230A	20.5	10.5	$1,113

All 3-ton central heat pumps

Heat pump vs. gas, propane and oilgas is cheaper to run

Yearly cost to heat a typical house (36,000 BTU/h of heat, 1,800 full-load hours) at Missouri prices.

Natural gas furnace, 95% AFUE$982/yr
Heat pump (typical, 9.0 HSPF2)$1,000/yr
Natural gas furnace, 80% AFUE$1,166/yr
Propane furnace, 95% AFUE$1,537/yr
Electric baseboard or furnace$2,638/yr
Heating oil, 85% AFUE$3,288/yr

Electricity and natural gas: Missouri residential averages from the U.S. EIA; propane and heating oil: latest EIA weekly prices.

Month by monthpeak $224 in January

Heating and cooling degree days (NOAA 1991-2020 normals) and what a typical 3-ton heat pump costs in each month at 13.9¢/kWh.

Month	Heating DD	Cooling DD	Cost
January	1,018	0	$224
February	795	0	$175
March	589	5	$131
April	282	27	$67
May	81	130	$45
June	5	311	$66
July	0	431	$90
August	1	372	$78
September	45	162	$44
October	261	36	$65
November	584	2	$129
December	885	0	$195

What size heat pump for a St. Louis home?4 ton for 2,000 sq ft

1,000 sq ft house2 ton · heating load 23,000 BTU/h
1,500 sq ft house3 ton · heating load 34,500 BTU/h
2,000 sq ft house4 ton · heating load 46,000 BTU/h
2,500 sq ft house5 ton · heating load 57,500 BTU/h

Average insulation, 8 ft ceilings. Size calculator for your own home

Questions4

Do heat pumps work in St. Louis winters?: St. Louis sees about 29 nights a year at or below 20°F. A cold-climate certified model keeps the house warm without leaning on backup heat. The average winter low is 27°F, and the heating season adds up to 4,547 heating degree days (NOAA 1991-2020 normals).
How much does it cost to run a heat pump in St. Louis?: A typical 3-ton central heat pump (17.0 SEER2, 9.0 HSPF2) uses about $1,000 of electricity a year for heating and $309 for cooling in St. Louis, at the Missouri average of 13.9¢/kWh. The most efficient models cost less - see the rankings above.
Is a heat pump cheaper than a gas furnace in St. Louis?: Not on heating alone at today's prices: about $1,000 a year with a typical heat pump versus $982 with a 95% gas furnace (Missouri averages: 13.9¢/kWh, $1.44/therm). A high-HSPF2 model narrows the gap, and a heat pump also replaces the air conditioner. Against propane, oil or electric heat it is usually far cheaper.
What size heat pump do I need for a 2,000 sq ft house in St. Louis?: With average insulation, roughly a 4-ton system: the estimated cooling load is 30,600 BTU/h and the heating load 46,000 BTU/h. Use the size calculator for your own house, and ask installers for a Manual J calculation.

Nearby cities

Climate: NOAA 1991-2020 normals, station CAHOKIA ST LOUIS AP (12 km away).