Use the chart below to find your mini split size by room square footage and climate zone. A 400 sq ft bedroom in a moderate climate needs 9,000-10,000 BTU; a hot climate pushes that to 12,000 BTU. All recommendations follow ACCA Manual J simplified factors. Need an exact number? Use our free calculator for a custom BTU in 60 seconds.
Mini Split Sizing Table: BTU by Square Footage & Climate Zone
Room Size
Mild Climate ~20 BTU/sq ft
Moderate ~25 BTU/sq ft
Hot Climate ~30 BTU/sq ft
Very Hot ~35 BTU/sq ft
100 sq ft
2,000 BTU
2,500 BTU
3,000 BTU
3,500 BTU
200 sq ft
4,000 BTU
5,000 BTU
6,000 BTU
7,000 BTU
300 sq ft
6,000 BTU
7,500 BTU
9,000 BTU
10,500 BTU
400 sq ft
8,000 BTU
10,000 BTU
12,000 BTU
14,000 BTU
500 sq ft
10,000 BTU
12,500 BTU
15,000 BTU
17,500 BTU
600 sq ft
12,000 BTU
15,000 BTU
18,000 BTU
21,000 BTU
800 sq ft
16,000 BTU
20,000 BTU
24,000 BTU
28,000 BTU
1,000 sq ft
20,000 BTU
25,000 BTU
30,000 BTU
35,000 BTU
1,200 sq ft
24,000 BTU
30,000 BTU
36,000 BTU
42,000 BTU
1,500 sq ft
30,000 BTU
37,500 BTU
45,000 BTU
52,500 BTU
How to read: Find your room’s sq ft on the left. Pick the climate column that matches your region (US zones 4-5, 3, 2, 1 respectively). The cell gives the base BTU requirement. Round to the nearest standard size (9k, 12k, 18k, 24k, 30k, 36k). For spaces over 1,000 sq ft, use a multi-zone system. Color key: green = single-zone small, amber = standard single-zone, orange = large single-zone, red = multi-zone or commercial.
Adjustments: When to Add More BTU
High Sun Exposure
South- or west-facing rooms: add +10% BTU. Skylights add +20%.
Poor Insulation
Pre-1980 homes without insulation upgrades: add +15-20% BTU.
High Occupancy
More than 2 people regularly in the room: add +600 BTU per extra person.
Example: 500 sq ft bedroom in Dallas (zone 2 = hot), south-facing, 2 occupants = 15,000 BTU (base) + 1,500 (sun) = 16,500 BTU, rounded up to 18,000 BTU.
Standard Mini Split Sizes: 9k vs 12k vs 18k vs 24k vs 30k vs 36k
Feature
9,000 BTU (0.75T)
12,000 BTU (1T)
18,000 BTU (1.5T)
24,000 BTU (2T)
Room Coverage (moderate climate)
250–400 sq ft
400–600 sq ft
600–800 sq ft
800–1,200 sq ft
Typical Power Draw (cool)
600–900W
900–1,300W
1,300–1,900W
1,800–2,500W
Noise (indoor, low fan)
19–30 dB
21–34 dB
25–38 dB
28–42 dB
SEER2 Range
17–30
17–28
16–24
16–22
Single-Zone Installed Cost
$1,500–$2,800
$1,800–$3,200
$2,500–$4,500
$3,200–$5,500
Best For
Bedrooms, offices
Living rooms, small additions
Open living areas, garages
Whole-floor, large open spaces
IECC Climate Zone Reference
The International Energy Conservation Code (IECC) divides the US into 8 climate zones based on heating/cooling degree days. Use this to pick which column of the chart above matches your location.
Zone 1 (Hot-Humid)
Miami, Houston, Honolulu
30-35 BTU/sq ft
Zone 2 (Hot)
Phoenix, Dallas, Atlanta
25-30 BTU/sq ft
Zone 3 (Warm)
Memphis, Charlotte, Albuquerque
22-25 BTU/sq ft
Zone 4 (Mixed)
New York, Chicago, Boston
20-25 BTU/sq ft
Zone 5 (Cool)
Minneapolis, Portland, Seattle
18-22 BTU/sq ft
Zone 6 (Cold)
Anchorage, Buffalo, Fargo
15-20 BTU/sq ft
Zone 7 (Very Cold)
Duluth, International Falls
12-15 BTU/sq ft
Zone 8 (Subarctic)
Barrow, Alaska
Use full Manual J
Mini Split Sizing FAQ
How do I use this mini split sizes chart?
Find your room's square footage in the left column. Pick the climate column that matches your region (mild, moderate, hot, or very hot — based on IECC climate zone). The intersecting cell gives the base BTU requirement. Apply adjustments: +10% for south/west exposure, +15-20% for poor insulation, +600 BTU per extra occupant. Round to the nearest standard size: 9k, 12k, 18k, 24k, 30k, 36k.
What size mini split for a 1,000 sq ft space?
A 1,000 sq ft space in a moderate climate (zone 3-4) needs 25,000 BTU. For open floor plans, use a multi-zone system with 2-3 indoor heads. For hot climates (zones 1-2), 1,000 sq ft often needs 30,000 BTU. Ceiling height and window exposure can push this 20-30% higher.
What BTU per square foot do I need?
20-25 BTU per square foot for well-insulated homes in mild climates, 25-30 BTU for moderate insulation and hot climates, 30-35 BTU for very hot or poorly insulated spaces. For accurate sizing, use ACCA Manual J load calculation accounting for windows, insulation, ceiling height, and sun exposure.
How do I know my IECC climate zone?
The IECC climate zone map is published by the DOE and ICC. Zone 1 covers hot-humid areas like Miami and Houston; Zone 8 covers subarctic Alaska. Most US homes fall in zones 3-5. Look up your zone at the DOE Energy Code website or your local building department.
Need an Exact BTU Recommendation?
Our free calculator factors in room size, climate zone, insulation, and sun exposure for a custom BTU in 60 seconds.
Each pick is matched to its ACCA Manual J BTU range. We verify specs against manufacturer data and sort by value — never by commission. Read our product policy.
Best 9,000 BTU Mini Splits — ~400 sq ft
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DELLA Vario Series 9000 BTU Mini Split Air Conditioner, Work with Alexa and Wifi, 20 SEER2, Energy Star, 0.75 Ton, Cools Up to 400 Sq.Ft, Ductless Inverter System, Heat Pump Pre-Charged, 16.4ft Kits #ad
MRCOOL 9000 BTU 115V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Easy Pro Series - Wall-Mounted AC Unit w/ Heating and Cooling for Home, Office & Commercial Space #ad
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OLMO 9,000 BTU 115V Single Zone Wall Mount Ductless Mini Split Air Conditioner & Heat Pump – 16FT Installation Kit & Smart Kit Included – 20 SEER2 Inverter System – Pre-Charged Refrigerant #ad
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DELLA Vario Series Mini Split Air Conditioner Works with Alexa,9000 BTU,Cools up to 400 Sq.Ft,19 SEER2,Ductless Inverter System,Energy Star,Heat Pump Pre-Charged and 16.4ft Installation Kits #ad
DELLA Serena Series 9000 BTU Mini Split AC, Energy Star 22 SEER2 230V, 0.75 Ton Inverter Heat Pump Ductless AC System for Rooms up to 400 Sq.Ft, WiFi & Alexa Control, Pre-Charged, 16.4ft Install Kit #ad
Garvee 9000 BTU Mini Split AC/Heating System, 19 SEER2 115V WIFI Enabled Energy Efficient Mini Split Air Conditioner,Wall-Mounted Split AC Unit,Cools Up to 450 Sq.Ft, Heat Pump & Installation Kits #ad
OLMO 12,000 BTU 230V Mini Split AC Heat Pump, Ductless Wall Mount - 20 SEER2 - Smart Kit & 16FT Installation Kit Included - Pre-Charged with R-32-1 Ton Inverter System #ad
DELLA Vario Series 12000 BTU Mini Split Air Conditioner Work with Alexa with 1 Ton Pre-Charged Heat Pump Ductless Inverter System, 23 SEER2, Cools Up to 550 Sq. Ft,16.4ft Installation Kit Included #ad
COSTWAY 12000BTU Mini Split Air Conditioner& Heater, 20 SEER2 115V Wall-Mounted Ductless AC Unit Cools Rooms up to 750 Sq. Ft, Energy Efficient Inverter AC with Heat Pump (Blast Series) #ad
DELLA Vario Series 12000 BTU Mini Split AC, Work with Alexa and Wifi, 20.5 SEER2 Cools Up to 550 Sq.Ft, Energy Efficient, 115V Ductless Inverter System, Pre-Charged Heat Pump and 16.4ft Kits #ad
DELLA Motto Series 12000 BTU 20 SEER2 115V Mini Split AC, Cools Up to 550 Sq.Ft, Works with Alexa and Wifi, Ductless Inverter System Air Conditioner, Pre-Charged Heat Pump and 16.4ft Kits #ad
YITAHOME 12000 BTU Mini Split AC/Heating System, Ductless Mini Split Air Conditioner Heat Pump,115V 20 SEER2 Energy Efficient Inverter AC Unit,Wifi Enabled Compatible with Alexa for Apartment, Garage #ad
MRCOOL 12000 BTU 115V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, 5th Gen DIY - Wall-Mounted AC Unit w/ Heating and Cooling for Home, Office & Commercial Space #ad
DELLA Serena 22 SEER2 12000 BTU Mini Split Heat Pump Works with Alexa, Energy Star 1 Ton Pre-Charged 230V Ductless AC Unit Inverter Air Conditioner System for Rooms up to 550Sq.Ft, 16.4ft Install Kit #ad
YITAHOME 20 SEER2 12000BTU Mini Split AC/Heating System 115V, Pre-charged Inverter AC Cool & Heat Up to 750 Sq. Ft, 3 Level Eco Mode, Complete Installation Kit, White #ad
Garvee 12000 BTU Mini Split Air Conditioner,22 SEER2 Ductless Inverter AC w/ 115V, Cool Up to 750 Sq. Ft with Heat Pump System, Compatible with Alexa, White #ad
Cooper & Hunter Dual Zone 9,000 + 12,000 BTU Ductless Mini Split AC/Heating System, Pre-Charged, Heat Pump, 21.3 SEER Including 25FT Copper Line Set And Communication Wires #ad
MRCOOL 18000 BTU 230V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Advantage Series - Wall-Mounted AC Unit w/Heating and Cooling for Home, Office & Commercial Space #ad
MRCOOL 18000 BTU 230V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Advantage Series - Wall-Mounted AC Unit w/Heating and Cooling for Home, Office & Commercial Space #ad
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COSTWAY 18,000 BTU Mini Split Air Conditioner, Energy Star, with Heat Pump, 21 SEER2 Inverter Split AC Unit with 24H Timer, Remote Control for Rooms up to 1250 Sq.Ft (Airtural Series) #ad
YITAHOME 18000 BTU Mini Split AC/Heating System, WiFi Enabled 21 SEER2 208-230V Inverter Pre-charged AC Compatible with Alexa, Cool Up to 1250 Sq. Ft, Complete Installation Kit, 1.5 Ton #ad
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MRCOOL 18000 BTU 230V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Easy Pro Series - Wall-Mounted AC Unit w/ Heating and Cooling for Home, Office & Commercial Space #ad
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MRCOOL 24000 BTU 230V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Easy Pro Series - Wall-Mounted AC Unit w/Heating and Cooling for Home, Office & Commercial Space #ad
MRCOOL 24000 BTU 230V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Easy Pro Series - Wall-Mounted AC Unit w/Heating and Cooling for Home, Office & Commercial Space #ad
COSTWAY 24000BTU Mini Split Air Conditioner& Heater,18.5 SEER2 208-230V Wall-Mounted Ductless AC Unit Cools Rooms up to 1500 Sq. Ft, Energy Efficient Inverter AC w/Heat Pump (Blast Series) #ad
DELLA Vario Series 24000 BTU Mini Split AC, 2 Ton 21 SEER2, Work with Alexa and Wifi, 230V Ductless Inverter System, Cools Up to 1500 Sq.Ft, Pre-Charged Heat Pump and 16.4ft Installation Kits #ad
DELLA Econo Series 23000 BTU Mini Split Air Conditioner 17 SEER2, 230V Cools up to 1500 Sq. Ft, Works with Alexa and Wifi, Heater Ductless Inverter System with Heat Pump,16.4ft Installation Kit #ad
YITAHOME 21 SEER2 24000 BTU Mini Split AC/Heating System, 208-230V Pre-charged Inverter System with Wi-Fi&Alexa Compatibility, Cover Up to 1500 Sq. Ft, Complete Installation Kit Included #ad
MRCOOL 24000 BTU 230V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Easy Pro Series - Wall-Mounted AC Unit w/ Heating and Cooling for Home, Office & Commercial Space #ad
24000 BTU Mini Split Air Conditioner 230V, 19 SEER2 AC & Heat Pump, Quiet Ductless System for Up to 1500 Sq.Ft, R32 Refrigerant, WiFi Smart Control, Indoor & Outdoor Units, Installation Kit #ad
DELLA Serena Series 22 SEER2 23000 BTU Mini Split, Works with Alexa and Wifi, Energy Star, 230V, 2 Ton Pre-Charged, Ductless AC Unit Inverter Heat Pump System for Rooms up to 1500 Sq.Ft, 16.4ft Kit #ad
Albott Mini Split Air Conditioner and Heater, 24,000 BTU, SEER2 18, 208-230V Inverter Energy-Efficient AC with Self-Cleaning, Remote and APP Control, Easy Installation, Cools up to 1550 Sq.Ft. #ad
YITAHOME 20 SEER2 24000BTU Mini Split AC/Heating System 208-230V, Pre-charged Inverter AC Cool & Heat Up to 1500 Sq. Ft, Pure Design, Compatible with 3 Level Eco Mode, Complete Installation Kit, White #ad
YITAHOME 24000 BTU Mini Split AC/Heating System, Ductless Mini Split Air Conditioner Heat Pump,230V 20 SEER2 Energy Efficient Inverter AC Unit,Wifi Enabled Compatible with Alexa for Apartment, Garage #ad
MRCOOL 36000 BTU 230V Ductless Inverter Mini Split Air Conditioner & Heat Pump System, Advantage Series - Wall-Mounted AC Unit w/Heating and Cooling for Home, Office & Commercial Space #ad
DELLA Vario Series 36,000 BTU 3 Ton 19 SEER2 Ductless Mini Split AC, Pre-Charged Heat Pump, 230V Energy Efficient Inverter System, Work with Alexa, Cools up to 2500 Sq.Ft, 16.4ft Installation Kit #ad
TURBRO 36,000 BTU Dual Zones Mini Split AC/Heat Pump, 22.5 SEER2, R454B, Ductless Inverter, WiFi, Greenland (2 x 18K), 230V, includes 36ft copper linesets for whole home, 2 rooms, open floor plan #ad
MrCool DIY 36k BTU 18 SEER2 Ductless Mini Split AC & Heat Pump w/ 25ft Lineset - 5th Generation - Energy Star 230v with 1 YR Labor Warranty by IWAE #ad
Albott Mini Split Air Conditioner and Heater, 36,000 BTU, SEER2 18, 208-230V Inverter Energy-Efficient AC with Self-Cleaning, Remote and APP Control, Easy Installation, Cools up to 2500 Sq.Ft. #ad
YITAHOME 3 Zone 36000 BTU Mini Split AC/Heating System, 20 SEER2 12000 BTU WiFi Enabled 115V Multi Zone Ductless Air Conditioner with 3 Outdoor Units, Enable Different Modes Simultaneously #ad
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YITAHOME 2 Zone 36000 BTU Mini Split AC/Heating System, 19 SEER2 18000 BTU WiFi Enabled 230V Dual Zone Ductless Air Conditioner with 2 Outdoor Units, Enable Different Modes Simultaneously #ad
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