What size mini-split do I need for 1,000 square feet?

About 24,000 to 30,000 BTU. In a mixed climate like Atlanta the estimate is 24,000 BTU (cooling load 19,500 BTU/h, heating load 19,000 BTU/h). Hot climates need more cooling capacity and cold climates more heating capacity, as the table shows.

How many BTU do I need for 1,000 square feet?

For cooling, roughly 21,300 BTU/h in a hot, dry climate and 16,800 BTU/h in a cold one. For heating, from 15,000 to 30,000 BTU/h depending on how cold winters get. Older, drafty homes need up to 30% more.

Is it better to oversize or undersize a heat pump?

Neither, but slight undersizing is usually less harmful for cooling. An oversized unit short-cycles and leaves the air clammy. In cold climates, size for the heating load and check the unit’s output at 5°F, or plan for backup heat on the coldest nights.

What size mini-split for 1,000 sq ft?

Short answer: 24,000 to 30,000 BTU, depending on your climate and insulation. In a mixed climate like Atlanta: 24,000 BTU.

By climate

Average insulation, 8 ft ceilings, three occupants.

Best 24,000 BTU mini-splits

Most efficient

SLIMAIR SHC24VH2AG

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

SEER2: 27.5
HSPF2: 14.5
Heat at 5°F: 27,000

Top-rated certified model in the size most 1,000 sq ft rooms need.

Full specs and running cost

Best for cold winters

MDV M3OX430-27HFN8-M1

24,000 BTU mini-split · M3O Series · cold-climate certified

SEER2: 22.5
HSPF2: 10.0
COP at 5°F: 2.80

Cold-climate certified, best efficiency at 5°F in this size.

Full specs and running cost

Compare all 24,000 BTU mini-splits

Work it out for your room

Pre-filled with 1,000 sq ft. Pick your city and adjust insulation, sun and ceiling height.

Your space

Area to heat and cool sq ftCeiling heightInsulationSun exposurePeople who usually use itIncludes the kitchen?

Your climate

StateCity

Mini-split size: 24,000 BTU
Central / ducted size: 2 ton
Cooling load: 21,300 BTU/h
Heating load: 15,000 BTU/h

See 24,000 BTU mini-splits See 2-ton central heat pumps

Rule-of-thumb estimate: cooling follows the ENERGY STAR room sizing table, heating uses typical BTU per square foot for the climate (NOAA 1991-2020 heating degree days). For a whole-house system, ask your installer for a Manual J load calculation.

More detail

Cooling and heating loads by climateBTU/h

Hot and dry (Phoenix)cooling 21,300 · heating 15,000
Hot and humid (Houston)cooling 21,300 · heating 15,000
Mixed (Atlanta)cooling 19,500 · heating 19,000
Cold (Chicago)cooling 18,600 · heating 27,000
Very cold (Minneapolis)cooling 16,800 · heating 30,000

Cooling follows the ENERGY STAR sizing table; heating uses BTU per sq ft for the climate (NOAA 1991-2020 normals).

How insulation changes the sizein Atlanta

Poor24,000 BTU · heating 24,700 BTU/h
Average24,000 BTU · heating 19,000 BTU/h
Good18,000 BTU · heating 15,200 BTU/h
Very good18,000 BTU · heating 12,400 BTU/h

Top 5 24,000 BTU mini-splitsranked by SEER2

#	Model	SEER2	EER2	HSPF2	COP at 5°F
1	SLIMAIR SHC24VH2AG	27.5	14.3	14.5	2.10
2	Blueridge BXS6Z24UC0also sold as 6 other model numbers	27.0	14.0	10.0	1.80
3	TOSOT TW24HAY32A1DO	27.0	14.0	10.0	1.80
4	TOSOT TW24WH29D6DOalso sold as 1 other model number	27.0	14.0	10.0	1.80
5	TOSOT TWH24AD32AOalso sold as 4 other model numbers	27.0	14.0	10.0	1.80

Questions3

What size mini-split do I need for 1,000 square feet?: About 24,000 to 30,000 BTU. In a mixed climate like Atlanta the estimate is 24,000 BTU (cooling load 19,500 BTU/h, heating load 19,000 BTU/h). Hot climates need more cooling capacity and cold climates more heating capacity, as the table shows.
How many BTU do I need for 1,000 square feet?: For cooling, roughly 21,300 BTU/h in a hot, dry climate and 16,800 BTU/h in a cold one. For heating, from 15,000 to 30,000 BTU/h depending on how cold winters get. Older, drafty homes need up to 30% more.
Is it better to oversize or undersize a heat pump?: Neither, but slight undersizing is usually less harmful for cooling. An oversized unit short-cycles and leaves the air clammy. In cold climates, size for the heating load and check the unit’s output at 5°F, or plan for backup heat on the coldest nights.

Other sizes

All sizing guides