MRCOOL DIY 18K Hyper Heat Mini Split System – 5th Gen, -22°F Heating, 21.2 SEER2, Pre-Charged DIY Line Set

New for 2025 – True -22°F Hyper Heat Performance with DIY Installation

The MRCOOL® DIYHH-18 Hyper Heat 18K Mini Split is the first 5th Generation DIY system engineered for true cold-climate installs down to -22°F. This complete bundle includes the DIYHH-18 outdoor condenser and the DIY-18-HP-WMAH-230D25-O wall-mounted air handler, delivering powerful heating and cooling for spaces up to 800 sq. ft.

Unlike traditional mini split systems, the MRCOOL DIY series uses factory-sealed QuickConnect® pre-charged line sets filled with R-454B low-GWP refrigerant, requiring no vacuum pump, gauges, nitrogen, or HVAC certification. This system installs quickly, safely, and cleanly—designed specifically for homeowners.

What's Included

• DIYHH-18-HP-C-230D25-O — 18K Hyper Heat Outdoor Condenser
• DIY-18-HP-WMAH-230D25-O — 18K Wall-Mounted Air Handler
• DIY25-1412 — 25 ft Pre-Charged QuickConnect® Line Set
• DIYPRO® Cable
• Wireless Remote + Manuals + Mounting Hardware

ℹ️ Line Set Length Info

This system includes a standard 25 ft. line set. Extended line set options add an additional line set, couplers, and a longer control wire for installations requiring extra distance.

Condenser Specifications – DIYHH-18-HP-C-230D25-O

Performance
BTU Rating	18,000 BTU Heating & Cooling
SEER2	21.2
EER2	12.5
HSPF2-4	11
HSPF2-5	8.5
Min Ambient Heat	-22°F
Operating Temp Range	-22°F to 122F
Compressor	Inverter Rotary
CFM	1765.8
Electrical
Voltage	208/230V
Phase	1
Cycle	60Hz
Min Circuit Ampacity	19A
Max Fuse	25A
Refrigeration
Refrigerant	R-454B
Factory Charge Volume	52.21 oz
Line Set	25 ft Pre-Charged QuickConnect®
Max Supported Line Length	75 ft
Liquid Line	1/4 in
Suction Line	1/2 in
Metering Device	Electronic Expansion Valve (EEV)
Noise
Condenser Noise	58 dBA
Dimensions
Net Dimensions	35.04” W × 26.5” H × 13.46” D
Net Weight	99.87 lbs
Gross Dimensions	40.55” W × 29.53” H × 18.11” D
Gross Weight	120.15 lbs

Wall Mount Air Handler – DIY-18-HP-WMAH-230D25-O

Performance
BTU Capacity	18,000 BTU
Coverage Area	Up to 800 sq. ft.
Fan Speeds	5-Speed
Quiet Mode	Yes
Noise Level	19 dBA (Low) – 54.5 dBA (High)
Dimensions
Net Dimensions	42.52” W × 13.19” H × 8.9” D
Net Weight	35.49 lbs
Gross Dimensions	46.73” W × 14.29” H × 17.68” D
Gross Weight	49.6 lbs

Smart Features

• MRCOOL SmartHVAC App
• iOS + Android Compatible
• Alexa & Google Assistant Voice Control
• Wireless Remote Included

Warranty

• 7-Year Compressor Warranty (Registered)
• 5-Year Parts Warranty (Registered)
• Extended Limited Lifetime with MRCOOL Care