Brand

MRCOOL mini splits

MRCOOL made do-it-yourself mini splits mainstream, and that's still the reason to choose one. Its DIY systems come with refrigerant lines that are pre-filled and connect without a vacuum pump, gauges or flaring. A capable homeowner can put one in over a weekend and keep the warranty. EPA's Section 608 guidance says connecting pre-charged lines still requires technician certification, so check that before you plan the job.

You pay for that design. On the equipment alone, a comparable system that a pro installs often costs less and performs the same. On the finished install, MRCOOL often wins by thousands, because the contractor's bill disappears. The range covers: - single rooms, with 115-volt options at the small end; - a Hyper Heat line for cold climates; - multi-zone systems for three to six rooms.

Who should buy MRCOOL: a confident DIYer heating and cooling one to six rooms, who wants the job done on their own schedule. Who should skip it: anyone hiring a contractor anyway. At that point you're paying the DIY premium and the install bill, and the pro-install brands give you more for the money.

Finder Brand Site

Data completeness: 60%

Source-backed systems: 12/5
Last sourced: Aug 17, 2026

Products

Capacity range

9k BTU to 36k BTU

Price band

$2,532 to $3,173

Cold-weather options

Overview

Positioning: DIY install systems present
Country: not published
Efficiency range: SEER2 18 to 23.6 / HSPF2 8.5 to 11.5
Warranty: Standard 5-year parts plus 7-year compressor; Extended Limited Lifetime Replacement only via paid MRCOOL Care Kit enrollment with conditions. Registration programs may vary by channel.
Dealer/DIY policy: The tracked MRCOOL DIY systems are marketed as DIY kits; final electrical, permitting, and code decisions still need qualified local review.

What to know about MRCOOL

The value is the install, not the hardware. You pay a little more for the equipment so you can skip the contractor.
Pre-filled lines trade flexibility for simplicity. They come in fixed lengths, and a damaged line set is a bigger problem than copper a technician can re-flare.
The "24k" is really a 23,000 BTU system. Its model page shows the certified figure.
Most buyers get a 5-year parts and 7-year compressor warranty. The headline "lifetime" compressor coverage needs a paid enrollment.
Think twice about the 36,000 BTU. It's far less efficient than every other MRCOOL single-room system. Two smaller systems usually cost less to run, and they let you control each room separately.
Hyper Heat is free at 12,000 BTU and a trade at 18,000.
The 12k Hyper Heat is just as efficient for cooling as the standard 12k, and it keeps heating 9 degrees colder.
At 18k, the cold-climate version gives up some efficiency. Buy it for genuinely deep cold, not by default.
Only the 9k and 12k run on 115 volts. Everything bigger needs a 240-volt circuit, the part of a "no contractor" budget people most often underestimate.
For deep cold across several rooms, there's one choice. The 6-zone 55k is the only MRCOOL multi-zone rated to -22F; the rest stop at -13F.

MRCOOL sizes and capacities

For an average room with average insulation, roughly:

9,000 BTU (115V) - a bedroom or office up to about 350 sq ft. The most efficient in the line, and the most common first MRCOOL.
12,000 BTU (115V) - a large bedroom, a living room or an insulated garage up to about 475 sq ft. The best seller, and the size where Hyper Heat costs you nothing.
18,000 BTU (230V) - an open living area up to about 700 sq ft. The first size that needs a 240-volt circuit.
23,000 BTU (sold as "24k", 230V) - a large open area up to about 900 sq ft.
36,000 BTU (230V) - a whole floor or a shop up to about 1,400 sq ft. Compare it against two smaller systems first.

Sun, high ceilings, kitchens and big windows all push these up, so run the sizing calculator for your room. Oversizing is the most common MRCOOL mistake: a system that's too big switches on and off constantly and leaves the room clammy.

MRCOOL multi-zone options

MRCOOL's multi-zone systems run one outdoor unit to several indoor units, each with its own thermostat:

3-zone (18k) - three small-to-medium rooms, often two bedrooms and a living room.
4-zone (27k) - four rooms, or three plus a bigger main space.
5-zone (36k) - most of a small house.
6-zone (48k and 55k) - the whole home. The 55k is the only one rated to -22F.

One outdoor unit means fewer holes in the wall. But it's less efficient when only one room is calling, and a breakdown takes out every room. For two rooms, two single-zone systems are usually the better buy.

Product table

DIY 5th Generation / DIY install
MRCOOL DIY 5th Gen 9,000 BTU (115V)
Capacity
9,000BTU/h
Voltage
115V
Efficiency
SEER2 23.6 / HSPF2 11.5
Low ambient
-13F
Data completeness: 88%
Sourced Aug 2026
DIY 5th Generation / DIY install
MRCOOL DIY 5th Gen 12,000 BTU (115V)
Capacity
12,000BTU/h
Voltage
115V
Efficiency
SEER2 23.5 / HSPF2 10.2
Low ambient
-13F
Data completeness: 90%
Sourced Aug 2026
DIY 5th Gen Hyper Heat / DIY install
MRCOOL DIY Hyper Heat 5th Gen 12,000 BTU (230V)
Capacity
12,000BTU/h
Voltage
230V
Efficiency
SEER2 23.5 / HSPF2 10
Low ambient
-22F
Data completeness: 98%
Sourced Aug 2026
DIY 5th Generation / DIY install
MRCOOL DIY 5th Gen 18,000 BTU (230V)
Capacity
18,000BTU/h
Voltage
230V
Efficiency
SEER2 22.5 / HSPF2 11.5
Low ambient
-13F
Data completeness: 88%
Sourced Aug 2026
DIY 5th Gen Hyper Heat / DIY install
MRCOOL DIY Hyper Heat 5th Gen 18,000 BTU (230V)
Capacity
18,000BTU/h
Voltage
230V
Efficiency
SEER2 21.2 / HSPF2 11
Low ambient
-22F
Data completeness: 98%
Sourced Aug 2026
DIY 5th Generation / DIY install
MRCOOL DIY 5th Gen 24k marketed / 23,000 BTU rated (230V)
Capacity
23,000BTU/h
Voltage
230V
Efficiency
SEER2 22.7 / HSPF2 9.5
Low ambient
-13F
Data completeness: 88%
Sourced Aug 2026
DIY 5th Generation / DIY install
MRCOOL DIY 5th Gen 36,000 BTU (230V)
Capacity
36,000BTU/h
Voltage
230V
Efficiency
SEER2 18 / HSPF2 8.5
Low ambient
-13F
Data completeness: 83%
Sourced Aug 2026
DIY 5th Gen Multi-Zone / DIY install
MRCOOL DIY 5th Gen Multi-Zone 18k 3-Zone Outdoor Unit
Capacity
not published
Voltage
230V
Efficiency
SEER2 not published / HSPF2 not published
Low ambient
-13F
Data completeness: 97%
Sourced Aug 2026
DIY 5th Gen Multi-Zone / DIY install
MRCOOL DIY 5th Gen Multi-Zone 27k 4-Zone Outdoor Unit
Capacity
not published
Voltage
230V
Efficiency
SEER2 not published / HSPF2 not published
Low ambient
-13F
Data completeness: 97%
Sourced Aug 2026
DIY 5th Gen Multi-Zone / DIY install
MRCOOL DIY 5th Gen Multi-Zone 36k 5-Zone Outdoor Unit
Capacity
not published
Voltage
230V
Efficiency
SEER2 not published / HSPF2 not published
Low ambient
-13F
Data completeness: 97%
Sourced Aug 2026
DIY 5th Gen Multi-Zone / DIY install
MRCOOL DIY 5th Gen Multi-Zone 48k 6-Zone Outdoor Unit
Capacity
not published
Voltage
230V
Efficiency
SEER2 not published / HSPF2 not published
Low ambient
-13F
Data completeness: 97%
Sourced Aug 2026
DIY 5th Gen Multi-Zone / DIY install
MRCOOL DIY 5th Gen Multi-Zone 55k 6-Zone Outdoor Unit
Capacity
not published
Voltage
230V
Efficiency
SEER2 not published / HSPF2 not published
Low ambient
-22F
Data completeness: 97%
Sourced Aug 2026