MRCOOL DIY 12,000 BTU 23.5 SEER2 Hyper Heat Complete Mini-Split Heat Pump System DIYHH-12

MRCOOL DIY 12,000 BTU 23.5 SEER2 Hyper Heat Complete Mini-Split Heat Pump System DIYHH-12

The MRCOOL DIY Hyper Heat 12K Complete Mini-Split System is a homeowner-friendly heating and cooling solution engineered for true do-it-yourself installation. Designed with a pre-charged QuickConnect® line set and DIYPRO® communication cable, this system eliminates the need for vacuum pumps, refrigerant handling, or specialized HVAC tools. With a 12,000 BTU capacity and 23.5 SEER2 efficiency, it is ideal for conditioning spaces up to approximately 550 sq ft, such as bedrooms, offices, garages, workshops, and accessory dwelling units.

Built with Hyper Heat technology, this system delivers reliable heating performance in extreme conditions, maintaining heat output down to -22 °F. The inverter-driven outdoor condenser ensures stable operation, improved efficiency, and reduced energy consumption throughout the year. The wall-mounted indoor air handler operates quietly while distributing consistent airflow for enhanced comfort in both heating and cooling modes.

This complete bundle includes everything required for installation, including the outdoor condenser, indoor wall-mount air handler, a 25-foot factory-charged line set, remote control, and necessary installation accessories. Integrated Wi-Fi capability allows convenient system control using a mobile device or compatible smart assistants, offering flexible comfort management from virtually anywhere.

Durability is enhanced through the outdoor unit’s Gold Fin® anti-corrosion coating, providing added protection in humid or coastal environments. Combining professional-grade performance with DIY simplicity, the MRCOOL DIY Hyper Heat 12K system is a reliable solution for year-round indoor comfort.

Features

• True DIY installation with factory-sealed QuickConnect® line set

• Hyper Heat technology maintains heating down to -22 °F

• High efficiency performance with 23.5 SEER2 rating

• Single-zone system for spaces up to approximately 550 sq ft

• Inverter-driven rotary compressor for quiet, efficient operation

• Integrated Wi-Fi with SmartHVAC™ app compatibility

• Voice control support with Amazon Alexa and Google Assistant

• Multiple operating modes: Cool, Heat, Auto, Dry, Fan, Sleep

• Gold Fin® anti-corrosion coating on outdoor condenser

• Complete bundle including condenser, air handler, line set, remote, and accessories

Specifications

Outdoor Condenser — DIYHH-12-HP-C-230D25-O

• Cooling / Heating BTU: 12,000
• Voltage: 208/230V
• Phase: 1
• Max Coverage: 550 sq ft
• SEER2: 23.5
• HSPF2-4: 10
• HSPF2-5: 8
• EER2: 12.8
• Inverter: Yes
• Min Ambient Heat: -22°F
• Min Ambient Cool: -22°F
• Max Line Set Length: 75 ft
• Line Size: 1/4” Liquid / 3/8” Suction
• Noise: 56.5 dB
• Compressor: Rotary DC inverter
• Breaker Size (Max Fuse): 15A
• Minimum Circuit Ampacity: 15A
• Refrigerant Type: R-454B (pre-charged)

Indoor Unit — DIY-12-HP-WMAH-230D25-O

• Cooling/Heating BTU: 12K
• Mounting: Wall
• Max Room: 550 sq ft
• Voltage: 208/230V
• Fan Speeds: 5
• Sound: 19–54.5 dB
• Modes: Cool / Heat / Auto / Dry / Fan / Sleep
• WiFi: Yes
• Smart Control: Alexa + Google
• Filter: Reusable
• Breaker: 15A shared system breaker

What's Included

✔ 1 × MRCOOL DIY Hyper Heat 12K Outdoor Condenser – DIYHH-12-HP-C-230D25-O

✔ 1 × MRCOOL 12K Wall-Mount Air Handler – DIY-12-HP-WMAH-230D25-O

✔ 25ft Pre-Charged QuickConnect® Line Set (DIY25-1438 recommended)

✔ DIYPro® communication cable

✔ Remote control

✔ Installation accessories

✔ User manual

IDEAL USE CASES

This 12K Hyper Heat system is ideal for:

• Bedrooms up to 550 sq ft
• Finished basements
• Home offices
• Airbnb suites
• Garage conversions
• Attic remodels
• Tiny homes
• She-sheds & man-caves
• ADUs & accessory buildings
• Detached workspaces
• Cabins or hunting lodges

Hyper Heat vs Standard DIY Mini Splits 

Standard DIY mini-splits are made for moderate climates and lose heating capacity when outdoor temperatures fall below freezing.

Hyper Heat technology keeps full proportional heating down to -22°F by using:

• DC inverter rotary compressor
• R-454B high-pressure refrigerant
• variable-speed outdoor fan
• electronic expansion valve (EEV)

Result:

Stable, silent, efficient heat even in extreme winter conditions.

This is why Hyper Heat is the correct choice for:

• Northern states
• Mountain towns
• Garage workshops
• Poorly insulated spaces

Frequently Asked Questions

Q: Do I need an HVAC tech to install this?

No. This is a true DIY system.

The line set is factory-sealed and pre-charged — no vacuum pump required.

Q: Can I mount the air handler myself?

Yes. Mounting bracket + hardware included.

Q: Does it heat well in winter?

Yes. This is Hyper Heat — maintains performance to -22°F.

Q: Do I need a separate breaker for the air handler?

No.

The outdoor 230V circuit powers the indoor unit.

Q: Can I expand this later?

This is a single-zone system.

If you want multiple rooms → choose a MRCOOL DIY Multi-Zone.

Q: Where can I get technical support?

You get direct support from MRCOOL Direct — USA’s #1 trusted MRCOOL dealer.