MRCOOL® DIY Hyper Heat 12K Complete Mini-Split System — DIYHH-12-HP-C-230D25-O Condenser + DIY-12-HP-WMAH-230D25-O Air Handler — 23.5 SEER2, 208/230V, 25ft Pre-Charged Line Set

Meet the First Ever DIY Hyper Heat Mini-Split System from MRCOOL®

For the first time ever, MRCOOL® has brought Hyper Heat technology to the DIY mini-split lineup. The DIYHH-12-HP-C-230D25-O condenser delivers 12,000 BTU heating and cooling and maintains powerful output down to -22°F, outperforming standard DIY units and traditional portable heaters.

No vacuuming, no charging, no guesswork—just connect the pre-charged QuickConnect® line set and turn it on.

Paired with the DIY-12-HP-WMAH-230D25-O wall-mounted air handler, this bundle gives you whisper-quiet operation, smart controls, WiFi, Amazon Alexa, Google Assistant compatibility, Dry Mode dehumidification, and a clean, sleek indoor design that fits any room.

True DIY Installation — Save $1,500–$3,000 plus in Labor

This system uses factory-sealed pre-charged refrigerant lines.

No HVAC tools. No nitrogen test. No vacuum pump.

Just install and go.

The included DIYPRO® cable eliminates conduit and provides extra protection from pets, weather, and lawn damage.

Cold Climate Performance You Can Actually Trust

Regular mini-splits lose heat as temps drop.

DIY Hyper Heat is different.

Its inverter compressor and R-454B refrigerant maintain stable output down to -22°F, eliminating the need for electric space heaters or propane.

That means:

✔ Better efficiency

✔ Lower bills

✔ Full comfort in bad winters

✔ Safe all-electric operation

Smart Comfort Anywhere

Control your system your way:

• Remote control
• SmartHVAC app (iOS / Android)
• Amazon Alexa / Google Assistant voice control

Built to Last — Gold Fin® Condenser

Salt air? Polluted areas? Humidity?

No problem.

The corrosion-resistant Gold Fin® coating protects the outdoor condenser and extends lifespan.

 WHAT’S INCLUDED IN THIS BUNDLE

✔ 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

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

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.

 

WHY BUY FROM MRCOOL DIRECT 

We are America’s #1 Most Trusted MRCOOL Dealer.

You get:

✔ Real HVAC support (phone & chat)

✔ Financing available

✔ Factory-fresh units (no reseller returns)

✔ Full warranty eligibility

✔ Fast replacement assistance

✔ And more

BUY DIRECT!

 Have questions? Call us at 615-553-8118

We make sure you order exactly what your space needs.