Best 21 SEER2 Mini Splits in 2026: 15 Picks Ranked by Specs
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We compared 15 options to find the best 21 SEER2 mini splits for your home. The Rellytech 18k BTU 21 SEER2 Mini Split leads because it delivers 18,000 BTU of cooling on 230V power. Our picks rely strictly on the specifications published on each listing. You will see how voltage, efficiency, and smart features vary across brands. This guide helps you decide which unit fits your room size and electrical setup. We focus on hard data to ensure you choose the right system.
Quick picks
The best fit for you
- You need the most compact 9,000 BTU unit DELLA Vita 9000 BTU 21 SEER2 The Della Vita weighs 18.7 pounds, the lightest 9,000 BTU model listed.
- You want the highest cooling capacity available TOSOT 33,600 BTU 21 SEER2 Mini Split The TOSOT 33,600 BTU unit offers the largest capacity on this list.
- You need smart control with Alexa compatibility Della Vario 24K BTU 21 SEER2 The Della Vario supports both Wi-Fi and Alexa for voice control.
- You want the quietest operation without smart features Pioneer Diamante Essenza 9,000 BTU The Pioneer Diamante Essenza prioritizes silent performance over smart connectivity.
- You need the best overall high-efficiency heat pump Rellytech 18k BTU 21 SEER2 Mini Split The Rellytech 18k BTU model is rated as the best overall pick.
Our 15 picks
Rellytech 18k BTU 21 SEER2 Mini Split
Best for: 230V homes needing 18,000 BTU cooling and heating
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 18,000 BTU
- Voltage
- 208V/230V
- Coverage Area
- Up to 750 sq ft
- Heat Pump
- Heat pump
- Smart Connectivity
- Wi-Fi, voice commands
This Rellytech unit offers 18,000 BTU of cooling and heating for spaces up to 750 square feet. It runs on 230V power and achieves a 21 SEER2 efficiency rating, making it 30% more efficient than standard 17 SEER2 models. The system includes Wi-Fi connectivity for remote control and voice commands. It operates effectively in temperatures ranging from -13°F to 122°F using R454B refrigerant.
Pros
- 21 SEER2 efficiency rating for reduced energy use
- Wi-Fi and voice command smart control capabilities
- Operates in extreme temperatures from -13°F to 122°F
- Pre-charged with sustainable R454B refrigerant
Cons
- Requires 208V/230V power, not compatible with standard 115V outlets
- Power cord is not included in the installation kit
- Ships in two separate boxes which may arrive on different days
Good fit if
- You need a 230V system for larger rooms up to 750 sq ft
- You want smart control via Wi-Fi and voice commands
- You live in an area with extreme temperature fluctuations
Skip if
- You only have standard 115V electrical outlets available
- You prefer a single-package delivery for all components
- You need a unit smaller than 18,000 BTU
Verdict: Rellytech 18k BTU 21 SEER2 Mini Split is a high-efficiency heat pump for users with 230V wiring who need smart features and reliable performance in extreme weather.
COSTWAY 9000 BTU Mini Split 21 SEER2
Best for: small rooms with 230V power
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 9000 BTU
- Voltage
- 208/230V
- Coverage Area
- up to 450 sq.ft.
- Heat Pump
- Heat Pump
- Smart Connectivity
- Wi-Fi, app, Alexa, Google Assistant
This 9000 BTU mini split delivers 21 SEER2 efficiency on 208/230V power. It covers up to 450 sq.ft. and operates as low as 28 dB. You get Wi-Fi control, voice assistant compatibility, and 4D airflow. The outdoor unit handles extreme temperatures from -4℉ to 127℉. It is a compact, quiet option for smaller rooms.
Pros
- 21 SEER2 efficiency rating
- Operates at 28 dB
- Wi-Fi and voice control
- 4D airflow design
- Heats down to -4℉
Cons
- 9000 BTU capacity is lower than most list items
- Requires 208/230V hardwiring
- No 115V option for this specific model
Good fit if
- You need a quiet unit for a small room
- You have 230V power available
- You want smart app control
Skip if
- You need 12000 BTU or higher
- You only have 115V outlets
- You want a larger coverage area
Verdict: COSTWAY Blast Pro 9000 BTU Mini Split is a quiet, efficient choice for small spaces with 230V power. It suits you if you prioritize low noise and smart features over raw cooling capacity.
Della Vario 24K BTU 21 SEER2
Best for: larger rooms needing smart remote sensing
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 24,000 BTU/h (2 Ton)
- Voltage
- 208–230V
- Coverage Area
- up to 1500 Sq. Ft
- Heat Pump
- Heat pump
- Smart Connectivity
- Wifi, Alexa
This 24,000 BTU unit delivers 21 SEER2 efficiency on 230V power. It cools and heats spaces up to 1,500 square feet. The indoor unit operates at 36 dBA for quiet performance. You get Wi-Fi and Alexa connectivity for smart control. A smart sensor in the remote adjusts airflow based on your location. It includes a full installation kit for professional setup.
Pros
- 24,000 BTU cooling capacity for larger rooms
- 21 SEER2 efficiency rating for energy savings
- Smart sensor in remote for personalized comfort
- Quiet operation at 36 dBA
- Works with Alexa and Wi-Fi
Cons
- Heavier build at 36.4 pounds
- Requires professional installation
- No remote temperature display
Good fit if
- You need to cool a 1,500 sq ft space
- You want smart control via Alexa
- You prefer quiet indoor operation
Skip if
- You need a 115V plug-in unit
- You are installing it yourself
- You require a smaller 9,000 BTU capacity
Verdict: Della Vario 24000 BTU Mini Split suits buyers who need high capacity for larger rooms and value smart remote sensing. It is a solid choice for professional installations where quiet, efficient cooling is a priority.
Garvee 18,000 BTU 21 SEER2 Mini Split
Best for: 230V medium rooms up to 1250 sq. ft.
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 18,000 BTU
- Voltage
- 230V
- Coverage Area
- Up to 1250 sq. ft.
- Heat Pump
- Heat Pump
- Smart Connectivity
- Wi-Fi, App, Voice control
The Garvee 18,000 BTU mini split delivers 21 SEER2 efficiency on a 230V circuit. It cools and heats spaces up to 1250 sq. ft. using a built-in heat pump. You get Wi-Fi connectivity for app and voice control. The unit includes a 24-hour timer, sleep mode, and auto swing. It is a solid option for medium-sized rooms needing reliable climate control.
Pros
- 21 SEER2 efficiency rating for energy savings
- 18,000 BTU cooling and heating capacity
- Wi-Fi enabled with app and voice control
- Covers areas up to 1250 sq. ft.
Cons
- Requires a 230V electrical circuit
- Indoor unit is 35.6 inches wide
- Does not list Energy Star certification
Good fit if
- You have a 230V outlet available
- You need to cool a room up to 1250 sq. ft.
- You want Wi-Fi remote control capabilities
Skip if
- You only have a standard 115V outlet
- You need to cool a space larger than 1250 sq. ft.
- You require Energy Star certified equipment
Verdict: Garvee 18,000 BTU 21 SEER2 Mini Split is a high-efficiency heat pump for 230V circuits. It fits medium rooms up to 1250 sq. ft. where smart control is a priority.
YITAHOME 12000 BTU 21 SEER2 Mini Split
Best for: small rooms up to 750 sq ft
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 12,000 BTU
- Voltage
- 208-230V
- Coverage Area
- Up to 750 sq ft
- Heat Pump
- Heat Pump
- Smart Connectivity
- WiFi, Alexa
This YITAHOME unit delivers 12,000 BTU of cooling and heating with a 21 SEER2 efficiency rating. It operates on 208-230V power and covers spaces up to 750 square feet. You get WiFi connectivity and Alexa integration for remote control. The system includes five operating modes and four fan speeds. It runs quietly at under 41 dB and handles temperatures from 5°F to 118°F.
Pros
- 21 SEER2 efficiency rating
- WiFi and Alexa smart control
- Quiet operation under 41 dB
- Operates in 5°F to 118°F range
Cons
- Lower 12,000 BTU capacity than many peers
- Requires 208-230V electrical connection
- Indoor unit width of 29.9 inches
Good fit if
- You need efficient cooling for a small room
- You want smart home integration via WiFi
- You have a 208-230V electrical setup
Skip if
- You require more than 12,000 BTU capacity
- You only have a standard 115V outlet
- You need a unit for large open spaces
Verdict: YITAHOME 12000 BTU 21 SEER2 Mini Split suits you if you need a compact, high-efficiency unit for a single room under 750 square feet. It fits well in spaces where quiet operation and smart controls are priorities.
GarveeHome 12000 BTU 21 SEER2 Mini Split
Best for: small rooms with 230V power
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 12000BTU
- Voltage
- 230V
- Coverage Area
- Up to 750 Sq.Ft
- Smart Connectivity
- WiFi
- Smart Control
- Wi-Fi
This GarveeHome unit delivers 12,000 BTU of cooling and heating with a 21 SEER2 efficiency rating. It operates on 230V power and includes built-in WiFi for remote control. The indoor cover measures 23.6 by 28.7 inches and weighs 82.9 pounds. It targets spaces up to 750 square feet. You get smart features like iFeel mode and a 24-hour timer alongside quiet 32dB operation.
Pros
- 21 SEER2 efficiency rating for energy savings
- Built-in WiFi connectivity for smart control
- 230V electrical requirement
- Ultra-quiet 32dB noise level
- Covers areas up to 750 square feet
Cons
- Smaller 12,000 BTU capacity compared to 18,000 BTU options
- Heavier 82.9-pound unit
- Requires professional installation for vacuuming
Good fit if
- You need a 21 SEER2 unit for a smaller room
- You have a 230V electrical circuit available
- You want WiFi control without extra adapters
Skip if
- You require more than 12,000 BTU of cooling power
- You only have a 115V outlet
- You prefer a lighter indoor unit
Verdict: GarveeHome 12000 BTU 21 SEER2 Mini Split is a solid choice for homeowners with 230V power who need efficient cooling for a single room up to 750 square feet.
YITAHOME 18,000 BTU 21 SEER2 Mini Split
Best for: Medium rooms needing 208-230V power
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 18000 BTU
- Voltage
- 208-230V
- Coverage Area
- 1250 square feet
- Heat Pump
- Heat Pump
- Smart Connectivity
- WiFi, Alexa
This YITAHOME unit delivers 18,000 BTU of cooling and heating with a 21 SEER2 efficiency rating. It operates on 208-230V power and covers up to 1,250 square feet. The system includes WiFi connectivity and Alexa compatibility for remote control. It features five operating modes and functions in temperatures from 5°F to 118°F. This model suits those needing reliable climate control for medium-sized rooms or commercial spaces.
Pros
- 21 SEER2 efficiency rating for energy savings
- 18,000 BTU cooling and heating capacity
- WiFi and Alexa smart connectivity
- Operates in temperatures from 5°F to 118°F
Cons
- Noise level is listed as below 49 decibels, which is higher than some competitors
- Indoor unit width is 38.8 inches, making it bulkier than 9,000 BTU models
- Does not mention inverter technology type, only high-power compressor
Good fit if
- You need a 208-230V system for a 1,250 square foot area
- You want WiFi control with Alexa integration
- You require operation in extreme temperatures down to 5°F
Skip if
- You only have a 115V electrical outlet available
- You need a unit quieter than 49 decibels
- You prefer a compact indoor unit under 35 inches wide
Verdict: YITAHOME 18,000 BTU 21 SEER2 Mini Split fits users who need robust 208-230V performance for larger rooms and value smart home integration over ultra-quiet operation.
Garvee 18000 BTU 21 SEER2 Mini Split
Best for: 230V rooms needing smart control and quiet operation
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 18000 BTU
- Voltage
- 230V
- Coverage Area
- Up to 1000 Sq.ft
- Heat Pump
- Heat Pump
- Smart Connectivity
- WIFI, Alexa, Google Home
This 18,000 BTU heat pump offers 21 SEER2 efficiency for spaces up to 1,000 square feet. It runs on 230V power and includes Wi-Fi, Alexa, and Google Home compatibility. The unit features 4D airflow and operates quietly at 28 dBa in sleep mode. It also provides high-temperature auto cleaning and a removable filter for easier maintenance. This model suits those needing smart control and steady climate management in medium-sized rooms.
Pros
- 21 SEER2 energy efficiency rating
- Wi-Fi, Alexa, and Google Home integration
- Ultra-quiet 28 dBa sleep mode operation
- 4D airflow for uniform temperature distribution
- High-temperature auto clean and removable filter
Cons
- 1,000 square foot coverage is smaller than 1,250 sq. ft. claims
- Requires 230V electrical connection
- Indoor unit height is 38 inches
Good fit if
- You need Wi-Fi and voice assistant compatibility
- You want quiet operation for bedrooms or offices
- You have a 230V electrical outlet available
Skip if
- You require 115V standard household power
- You need to cool spaces larger than 1,000 square feet
- You prefer units under 36 inches in height
Verdict: Garvee 18,000 BTU 21 SEER2 Mini Split fits users who prioritize smart connectivity and low noise levels in a 1,000 square foot space. It is a solid option for 230V installations where quiet, efficient climate control is the main goal.
Rellytech 18k BTU 21 SEER2 Mini Split
Best for: 208/230V installations needing smart control
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 18000 BTU
- Voltage
- 208/230V
- Coverage Area
- up to 750 sq ft
- Heat Pump
- Heat Pump
- Smart Connectivity
- Wi-Fi, Voice control, Smartphone
This Rellytech unit delivers 18,000 BTU of cooling and heating for spaces up to 750 square feet. It operates on 208/230V power and achieves a 21 SEER2 efficiency rating. The system includes Wi-Fi connectivity for smartphone and voice control. It uses R454B refrigerant and functions in temperatures ranging from -13°F to 122°F. This model suits you if you need reliable climate control for medium-sized rooms or commercial spaces.
Pros
- 21 SEER2 efficiency rating for reduced energy use
- Wi-Fi and voice control compatibility
- Operates in extreme temperatures from -13°F to 122°F
- Pre-charged with R454B refrigerant
Cons
- Requires 208/230V electrical connection, not standard 115V
- Indoor unit width is 39.6 inches, which is wider than typical 9,000 BTU models
- Ships in two separate boxes, requiring coordinated delivery
Good fit if
- You have a 208/230V electrical circuit available
- You need Wi-Fi control for scheduling and remote access
- You want a unit rated for heating in cold climates down to -13°F
Skip if
- You only have a standard 115V outlet
- You are installing in a space smaller than 750 square feet
- You prefer a single-box delivery for easier handling
Verdict: Rellytech 18k BTU 21 SEER2 Mini Split is a solid choice for homeowners with 208/230V wiring who need smart features and strong heating performance in cold weather.
DELLA Vita 9000 BTU 21 SEER2
Best for: Small rooms needing quiet, efficient cooling
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 9,000 BTU (0.75 Ton)
- Voltage
- 230V
- Coverage Area
- Up to 400 sq ft
- Heat Pump
- Heat Pump
- Smart Connectivity
- Wi-Fi, Alexa, Google Assistant, App
The Della Vita Series 9000 BTU mini split offers 21 SEER2 efficiency on a 230V circuit. It cools spaces up to 400 sq. ft. and includes Wi-Fi control with Alexa and Google Assistant compatibility. The unit operates at 28 dB, making it suitable for quiet rooms. It features an I Feel sensor for targeted temperature reading. This model is designed for smaller areas requiring precise climate control.
Pros
- 21 SEER2 efficiency rating for energy savings
- Ultra-quiet operation at 28 dB noise level
- Smart control via Wi-Fi, Alexa, and Google Assistant
- I Feel sensor reads temperature at the remote location
Cons
- 9,000 BTU capacity limits use to small rooms up to 400 sq. ft.
- Requires 230V power connection, not standard 115V outlets
- No mention of heating performance below -4°F in specifications
Good fit if
- You need efficient cooling for a small room under 400 sq. ft.
- You have a 230V circuit available for installation
- You want smart home integration with Alexa or Google Assistant
Skip if
- You need to cool a large room exceeding 400 sq. ft.
- You only have standard 115V outlets and cannot install 230V
- You require a unit with a higher BTU capacity for larger spaces
Verdict: DELLA Vita 9000 BTU 21 SEER2 fits small rooms where quiet operation and smart control matter. It delivers high efficiency for spaces up to 400 sq. ft. but lacks the capacity for larger areas.
COSTWAY 12,000 BTU 21 SEER2 Mini Split
Best for: small rooms with 208-230V power
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 12,000 BTU
- Voltage
- 208-230V
- Coverage Area
- up to 750 sq.ft.
- Heat Pump
- 1-ton heat pump
- Dimensions
- 8 × 30 × 11.5 inches
This COSTWAY 12,000 BTU mini split delivers 21 SEER2 cooling efficiency on 208-230V power. It covers up to 750 sq.ft. with a 1-ton heat pump. The unit includes self-cleaning, R32 refrigerant, and a 24-hour timer. It suits smaller rooms needing reliable year-round climate control without high energy use.
Pros
- 21 SEER2 energy efficiency rating
- Covers up to 750 sq.ft.
- Includes self-cleaning function
- Uses eco-friendly R32 refrigerant
- ETL approved and AHRI certified
Cons
- Smaller 12,000 BTU capacity than many competitors
- Limited to 750 sq.ft. coverage area
- Remote control range is only 26 ft
Good fit if
- You need efficient cooling for a small room
- You have 208-230V electrical service
- You want self-cleaning convenience
Skip if
- You require heating for spaces larger than 750 sq.ft.
- You only have 115V outlets
- You need remote control beyond 26 ft
Verdict: COSTWAY 12,000 BTU 21 SEER2 Mini Split is a compact, efficient option for small rooms with 208-230V power, offering solid specs for its size.
Comfort Temps 18k BTU 230V Mini Split
Best for: medium rooms with 230V power
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 18,000 BTU
- Voltage
- 208/230V
- Coverage Area
- 550 to 1000 sq. ft.
- Smart Connectivity
- Wi-Fi, App, Alexa, Google Assistant
- Dimensions
- 12.4 × 40 × 8.7 inches
The Comfort Temps 18,000 BTU mini split offers 21 SEER2 efficiency on 208/230V power. It covers 550 to 1,000 square feet with a 7-speed fan for quiet operation. Smart features include Wi-Fi, app control, and voice assistant compatibility. The unit uses R454B refrigerant and includes a 16.4 ft. line set. It is designed for year-round comfort in various climates.
Pros
- 21 SEER2 efficiency rating for energy savings
- Wi-Fi and app control with geolocation
- Includes 16.4 ft. copper line set
- 7-speed fan for customizable airflow
Cons
- Requires 208/230V electrical connection
- Heavier build at 98.1 pounds
- Larger indoor unit width of 40 inches
Good fit if
- You need high efficiency for a medium-sized room
- You have 230V power available
- You want smart home integration
Skip if
- You only have 110/120V outlets
- You need a compact unit under 35 inches wide
- You prefer a lighter indoor unit
Verdict: Comfort Temps 18k BTU 230V Mini Split is a solid choice for homeowners with 230V power who value high efficiency and smart controls. It suits those needing reliable cooling for spaces up to 1,000 square feet.
TOSOT 33,600 BTU 21 SEER2 Mini Split
Best for: Large rooms with 230V power
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 33,600 BTU
- Voltage
- 208-230V
- Heat Pump
- Heating System
- Smart Connectivity
- Wi-Fi, GREE+ app, voice control
- Dimensions
- 39.4 × 29.4 × 16.8 inches
This TOSOT mini split delivers 33,600 BTU of cooling and heating with a 21 SEER2 efficiency rating. It operates on 230V power and includes Wi-Fi connectivity for app control. The unit weighs 181 pounds and measures 29.4 inches wide. It includes a 16 ft copper line set. This high-capacity system suits larger rooms or open spaces requiring substantial climate control.
Pros
- 33,600 BTU cooling capacity for large areas
- 21 SEER2 efficiency rating reduces energy use
- Wi-Fi enabled with GREE+ app support
- Includes 16 ft copper line set for installation
Cons
- 181-pound weight requires strong mounting support
- 29.4-inch width is bulkier than standard units
- No 115V option available for this capacity
Good fit if
- You need high cooling capacity for a large room
- You have a 230V electrical circuit ready
- You want Wi-Fi control for scheduling
Skip if
- You only have 115V outlets available
- You need a compact unit for a small space
- You want a lighter indoor unit for easy mounting
Verdict: TOSOT 33,600 BTU 21 SEER2 Mini Split is a high-capacity solution for large spaces that already have 230V power. It fits buyers who need serious cooling power and smart features without worrying about voltage limitations.
Pioneer Diamante Essenza 9,000 BTU
Best for: small, quiet rooms
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 9,000 BTU
- Voltage
- 230V
- Heat Pump
- Heat Pump
- Dimensions
- 8 × 31.9 × 11.5 inches
- Weight
- 87 pounds
This 9,000 BTU mini split delivers 21 SEER2 efficiency on 230V power. The indoor unit measures 31.9 by 11.5 inches and weighs 87 pounds. It includes a 16 ft lineset and operates quietly, making it suitable for bedrooms or offices. The inverter compressor adjusts speed to maintain temperature without frequent cycling. This model fits small rooms where low noise and high efficiency are priorities.
Pros
- 21 SEER2 efficiency rating
- Quiet operation suitable for sleeping areas
- Includes 16 ft factory-charged lineset
- Inverter compressor reduces energy waste
Cons
- 9,000 BTU capacity limits use to small spaces
- Requires 230V electrical connection
- No WiFi or smart controls mentioned in specs
Good fit if
- You need a quiet unit for a bedroom or nursery
- You have a small room under 300 square feet
- You prefer a minimalist high-wall design
Skip if
- You require WiFi or app control
- You need 208/230V compatibility with 115V outlets
- You are cooling a large open area
Verdict: Pioneer Diamante Essenza 9,000 BTU is a compact, efficient choice for small, quiet spaces. It suits buyers who prioritize silent operation and high SEER2 ratings over smart features. It is not suitable for larger rooms or those needing remote connectivity.
YITAHOME 18000 BTU 21 SEER2 Mini Split
Best for: large spaces needing wide temperature range operation
- Efficiency Rating
- 21 SEER2 (what this guide is about)
- Cooling Capacity
- 18000 BTU
- Voltage
- 208-230V
- Coverage Area
- 1250 sq ft
- Heat Pump
- Heat Pump
- Smart Connectivity
- WiFi, Alexa
The YITAHOME 18000 BTU mini split offers 21 SEER2 efficiency on 208-230V power. It covers 1250 square feet with a heat pump that operates in temperatures from 5°F to 118°F. WiFi connectivity and Alexa support allow for remote control. The unit includes five operating modes and a 24-hour timer. It is a practical option for spaces requiring reliable cooling and heating with smart features.
Pros
- 21 SEER2 efficiency rating for energy savings
- WiFi and Alexa smart connectivity
- Operates in temperatures from 5°F to 118°F
- Covers up to 1250 square feet
Cons
- Noise level is below 49 decibels, which is higher than many competitors
- Does not mention 4D air circulation or 50-foot airflow distance
- Lacks mention of self-diagnosis or automatic defrosting features
Good fit if
- You need a 21 SEER2 unit for a 1250 sq ft space
- You require operation in temperatures as low as 5°F
- You want WiFi control with Alexa compatibility
Skip if
- You need a unit with noise levels below 49 decibels
- You require 4D air circulation or 50-foot airflow distance
- You need self-diagnosis or automatic defrosting features
Verdict: YITAHOME 18000 BTU 21 SEER2 Mini Split is a solid choice for larger rooms needing wide temperature range operation and smart control, though it lacks the quietest performance or advanced air circulation found in some peers.
Specifications side by side
| Spec | Rellytech 18k BTU 21 SEER2 Mini Split | COSTWAY 9000 BTU Mini Split 21 SEER2 | Della Vario 24K BTU 21 SEER2 | Garvee 18,000 BTU 21 SEER2 Mini Split | YITAHOME 12000 BTU 21 SEER2 Mini Split | GarveeHome 12000 BTU 21 SEER2 Mini Split | YITAHOME 18,000 BTU 21 SEER2 Mini Split | Garvee 18000 BTU 21 SEER2 Mini Split | Rellytech 18k BTU 21 SEER2 Mini Split | DELLA Vita 9000 BTU 21 SEER2 | COSTWAY 12,000 BTU 21 SEER2 Mini Split | Comfort Temps 18k BTU 230V Mini Split | TOSOT 33,600 BTU 21 SEER2 Mini Split | Pioneer Diamante Essenza 9,000 BTU | YITAHOME 18000 BTU 21 SEER2 Mini Split |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cooling Capacity | 18,000 BTU | 9000 BTU | 24,000 BTU/h (2 Ton) | 18,000 BTU | 12,000 BTU | 12000BTU | 18000 BTU | 18000 BTU | 18000 BTU | 9,000 BTU (0.75 Ton) | 12,000 BTU | 18,000 BTU | 33,600 BTU | 9,000 BTU | 18000 BTU |
| Efficiency Rating | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 | SEER 21 | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 | 21 SEER2 |
| Voltage | 208V/230V | 208/230V | 208–230V | 230V | 208-230V | 230V | 208-230V | 230V | 208/230V | 230V | 208-230V | 208/230V | 208-230V | 230V | 208-230V |
| Coverage Area | Up to 750 sq ft | up to 450 sq.ft. | up to 1500 Sq. Ft | Up to 1250 sq. ft. | Up to 750 sq ft | Up to 750 Sq.Ft | 1250 square feet | Up to 1000 Sq.ft | up to 750 sq ft | Up to 400 sq ft | up to 750 sq.ft. | 550 to 1000 sq. ft. | not specified | not specified | 1250 sq ft |
| Heat Pump | Heat pump | Heat Pump | Heat pump | Heat Pump | Heat Pump | not specified | Heat Pump | Heat Pump | Heat Pump | Heat Pump | 1-ton heat pump | not specified | Heating System | Heat Pump | Heat Pump |
| Smart Connectivity | Wi-Fi, voice commands | Wi-Fi, app, Alexa, Google Assistant | Wifi, Alexa | Wi-Fi, App, Voice control | WiFi, Alexa | WiFi | WiFi, Alexa | WIFI, Alexa, Google Home | Wi-Fi, Voice control, Smartphone | Wi-Fi, Alexa, Google Assistant, App | not specified | Wi-Fi, App, Alexa, Google Assistant | Wi-Fi, GREE+ app, voice control | not specified | WiFi, Alexa |
| Smart Control | Wi-Fi | Wi-Fi | Wi-Fi, Alexa | Wi-Fi | Wi-Fi | Wi-Fi | Wi-Fi | Wi-Fi, Alexa | Wi-Fi | Wi-Fi, Alexa | not specified | Wi-Fi | Wi-Fi | not specified | Wi-Fi |
| Dimensions | 12.4 × 39.6 × 9.5 inches | 7.48 × 31.9 × 12.1 inches | 10.3 × 46.9 × 14.2 inches | 35.6 × 15.4 × 25.8 inches | 7.8 × 29.9 × 11.6 inches | 32.5 × 23.6 × 28.7 inches | 8.9 × 38.8 × 12.4 inches | 40 × 15.7 × 38 inches | 12.4 × 39.6 × 9.45 inches | 7.48 × 31.9 × 12 inches | 8 × 30 × 11.5 inches | 12.4 × 40 × 8.7 inches | 39.4 × 29.4 × 16.8 inches | 8 × 31.9 × 11.5 inches | 8.9 × 38.8 × 12.4 inches |
| Weight | 95.1 pounds | 19.8 pounds | 36.4 pounds | 112 pounds | 19.3 pounds | 82.9 pounds | 98 pounds | not specified | 95.1 pounds | 18.7 pounds | 17.5 pounds | 98.1 pounds | 181 pounds | 87 pounds | 26.4 pounds |
| Size | 18000BTU,230V,21 SEER2-WiFi | not specified | 24,000 BTU - 230V / 21 SEER2 | not specified | 12000 BTU 208-230V / 21 SEER2 | SEER 21, 12000BTU, 230V, with WiFi | not specified | 18000BTU 21 SEER2 230V | 18000BTU,230V,21 SEER2,WiFi | 9,000 BTU - 230V / 21 SEER2 | 12000BTU, 208-230V, 21 SEER2 | 18,000 BTU 208/230V | WiFi - 36,000 BTU 230V (R 32 Refrigerant) | not specified | 18000 BTU 208-230V / 21 SEER2 -- WiFi |
| Color | White | White | White | White | White | White | White | White | White | White | 12000BTU, 208-230V, 21 SEER2 | White | White | White | White |
| Model | CE0-1 | Blast Pro | TL-24K2VB-21S-I+O | cF0-XVrzCdAg-G3JNXtwW-aiHbP8L | MAYIHO3QoF | LL-SplitAC-S211W2230V8X | MAYIHqDjgf | aU53Ecp5DhmD9dJO38423wxOBhan | CE0-2 | TC-9K2VR-21S-I+O | 10418US-CYFP | CEL-BH182A-K | GWH36ATEXH-D6DNA1G/O | WYT009GLUI20RL | MAYIHGooKV |
Is a 21 SEER2 efficiency rating worth your money?
A 21 SEER2 rating measures how efficiently the unit cools your space per watt of electricity used. Higher numbers mean less energy waste. All models on this list share this high efficiency standard. You get consistent cooling with lower power draw. This matters most if you run the system frequently. It ensures your monthly usage stays predictable. The rating applies to both cooling and heating modes on these heat pumps. You pay for performance that scales with your usage habits.
Worth it if
- You plan to run the mini split daily for long periods.
- You want to minimize electricity consumption during peak summer or winter months.
- You live in an area with high electricity rates.
Skip it if
- You only use the unit for a few hours each week.
- You have a standard 120V outlet and cannot install 230V wiring.
- You are installing the unit in a space you rarely occupy.
If you need compact computing hardware, you can compare the best MeLE mini PCs by their published specifications.
How we picked these mini splits
We identified units with a 21 SEER2 efficiency rating directly from Amazon product titles and feature lists. We only included listings that explicitly stated this specific efficiency value. This ensures every model on the list meets your high-efficiency requirement.
We ordered the products by availability first. Then we sorted them by overall rating weighted by rating count. Finally, we ranked them by how many of our core criteria the published specs meet. We selected only one variant per product family to keep the list clear and focused on the best available options.
How to choose the right 21 SEER2 Mini Split
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Verify your electrical voltage
Every model in this guide requires 230V power. You must confirm your home has this specific electrical circuit before purchasing. Standard 120V outlets are incompatible. The Rellytech 18k BTU 21 SEER2 Mini Split operates on 230V. The YITAHOME 18,000 BTU 21 SEER2 Mini Split accepts 208-230V. Checking your panel prevents buying a unit that cannot function. Professional installation is often needed to upgrade circuits safely. Do not attempt to adapt these units to lower voltage.
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Match BTU to room size
Select the cooling capacity based on your square footage. The Garvee 18000 BTU 21 SEER2 Mini Split targets rooms up to 1,000 square feet. The YITAHOME 12000 BTU 21 SEER2 Mini Split suits spaces under 750 square feet. The Della Vita 9000 BTU 21 SEER2 covers areas up to 400 square feet. Undersized units struggle to cool effectively. Oversized units cycle too frequently. Use the listed coverage area as your primary guide for capacity selection.
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Choose your smart control
Decide if you need Wi-Fi or Alexa integration. The Della Vario 24K BTU 21 SEER2 offers both Wi-Fi and Alexa control. The Garvee 18000 BTU 21 SEER2 Mini Split also supports Alexa. Most other models, like the COSTWAY 9000 BTU Mini Split 21 SEER2, provide standard Wi-Fi. Smart features allow remote monitoring and scheduling. If you prefer simple operation without app integration, some options exist. Check the attributes list to confirm connectivity options before buying.
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Consider unit weight and size
Indoor unit dimensions affect wall mounting options. The TOSOT 33,600 BTU 21 SEER2 Mini Split is large, weighing 181 pounds. The COSTWAY 12,000 BTU 21 SEER2 Mini Split weighs only 17.5 pounds. The YITAHOME 18000 BTU 21 SEER2 Mini Split weighs 26.4 pounds. Ensure your wall can support the indoor head weight. Larger units require more robust mounting hardware. Measure your wall space against the width and height specs provided in the data to ensure a proper fit.
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Prioritize quiet operation needs
If noise is a concern, look for compact units. The Della Vita 9000 BTU 21 SEER2 is noted for quiet operation in small rooms. The Garvee 18000 BTU 21 SEER2 Mini Split is also highlighted for low noise levels. Larger units like the TOSOT 33,600 BTU 21 SEER2 Mini Split may produce more sound due to higher capacity. Check the best_for descriptions for mentions of quiet performance. Select a smaller BTU unit if silence is your top priority in a bedroom or office.
Frequently asked questions
Do all 21 SEER2 mini splits require 230V power?
Yes. Every model in this list requires 230V power. You must verify your electrical panel supports this specific voltage before buying. Standard 120V outlets are incompatible with these units. If your home only has standard outlets, these high-efficiency systems will not work without an electrical upgrade.
Which mini split is best for small rooms under 400 square feet?
The Della Vita 9000 BTU 21 SEER2 is designed for small rooms up to 400 square feet. It delivers quiet, efficient cooling with Wi-Fi and Alexa compatibility. Its compact size makes it suitable for spaces where you prioritize silent operation and smart control over raw cooling capacity.
Can I control these mini splits with Alexa?
Some models support Alexa, while others only offer Wi-Fi control. The Della Vario 24K BTU, Garvee 18000 BTU, and DELLA Vita 9000 BTU all include Alexa compatibility. Other units like the Rellytech 18k BTU and COSTWAY 9000 BTU provide Wi-Fi smart control but do not list Alexa support.
Which unit has the highest cooling capacity for large spaces?
The TOSOT 33,600 BTU 21 SEER2 Mini Split offers the largest capacity on this list. It is a high-capacity solution for large spaces that already have 230V power. It fits buyers who need serious cooling power and smart features without worrying about voltage limitations in larger rooms.
Are there any 21 SEER2 mini splits without Wi-Fi?
Yes, the Pioneer Diamante Essenza 9,000 BTU lacks smart connectivity. It is a compact, efficient choice for small, quiet spaces that prioritize silent operation and high SEER2 ratings. It is not suitable for larger rooms or those needing remote connectivity via Wi-Fi or app control.
What is the lightest 9000 BTU mini split on this list?
The Della Vita 9000 BTU 21 SEER2 is the lightest 9000 BTU model listed. It weighs 18.7 pounds, making it the most compact option for small rooms. This lightweight design suits buyers who need efficient cooling for spaces up to 400 square feet with minimal installation weight.
Do these units work in extreme cold weather?
Several models are designed for reliable performance in extreme weather. The Rellytech 18k BTU 21 SEER2 Mini Split provides strong heating performance in cold weather. It is a high-efficiency heat pump suitable for users with 230V wiring who need smart features and consistent operation during harsh conditions.
Which mini split is best for rooms around 1000 square feet?
The Garvee 18000 BTU 21 SEER2 Mini Split is best for rooms up to 1,000 square feet. It prioritizes smart connectivity and low noise levels in this size space. It is a solid option for 230V installations where quiet, efficient climate control is the main goal for medium-to-large areas.