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MRCOOL® HyperHeat®

MRCOOL DIY 12K Hyper Heat Mini Split System – 5th Gen Wall Mount, -22°F Heating, 23.5 SEER2, Pre-Charged Line Set

MRCOOL DIY 12K Hyper Heat Mini Split System – 5th Gen Wall Mount, -22°F Heating, 23.5 SEER2, Pre-Charged Line Set

SKUMC-DIY-HH12-WM-25

TypeSingle Zone Mini Split System

Regular price $2,557.00
Sale price $2,557.00 Regular price $3,196.25
You Save: $639.25
SALE Sold out
Shipping calculated at checkout.

Refrigerant Type: R-454B

Line Set Length
In stock
Ready to ship
Free delivery*
Ships in 1–2 business days
Estimated arrival: Jul 10 – Jul 12
Based on order date & typical delivery times
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PRODUCT DESCRIPTION

MRCOOL DIY 12K Hyper Heat Complete Mini Split System – 5th Gen Wall Mount

The MRCOOL® DIY 12K Hyper Heat Complete Mini Split System is a 5th Generation single-zone ductless heat pump designed for true cold-climate heating and efficient cooling. This complete 208/230V bundle pairs the DIYHH-12-HP-C-230D25-O 12,000 BTU Hyper Heat outdoor condenser with the DIY-12-HP-WMAH-230D25-O wall-mounted air handler, making it an excellent choice for bedrooms, home offices, finished basements, garages, workshops, ADUs, cabins, and other spaces up to 550 sq. ft.

Built for real winter performance, this MRCOOL Hyper Heat system provides heating operation down to -22°F while delivering up to 23.5 SEER2 cooling efficiency. The included 25 ft pre-charged QuickConnect® line set allows for homeowner-friendly installation without a vacuum pump, refrigerant gauges, nitrogen, or field refrigerant handling.

Important: This is a 208/230V system. It does not work with 115V circuits or 115V air handlers. Because apparently electricity still insists on having rules.

What's Included in This Bundle?

  • DIYHH-12-HP-C-230D25-O – MRCOOL DIY Hyper Heat 12K Outdoor Condenser
  • DIY-12-HP-WMAH-230D25-O – MRCOOL 12K Wall-Mount Air Handler
  • 25 ft Pre-Charged QuickConnect® Line Set
  • DIYPRO® Communication Cable
  • Wireless Remote Control
  • Installation Accessories
  • Mounting Hardware
  • User Manual and Documentation

Key Features

  • 12,000 BTU heating and cooling capacity
  • Designed for rooms up to 550 sq. ft.
  • Hyper Heat performance down to -22°F
  • High-efficiency operation with up to 23.5 SEER2
  • DIY-friendly QuickConnect® pre-charged line set
  • No vacuum pump, gauges, nitrogen, or field refrigerant handling required
  • 208/230V single-zone system
  • DC inverter rotary compressor for efficient comfort control
  • Quiet wall-mounted indoor air handler
  • Built-in WiFi control with MRCOOL SmartHVAC™ App
  • Amazon Alexa® and Google Assistant® compatible
  • Gold Fin® anti-corrosion outdoor condenser coating
  • Reusable washable filter

Ideal Applications

  • Bedrooms up to 550 sq. ft.
  • Finished basements and bonus rooms
  • Home offices and studios
  • Garage conversions and workshops
  • Airbnb and short-term rental suites
  • Attic remodels and lofts
  • Tiny homes and cabins
  • She-sheds, hobby rooms, and detached workspaces
  • ADUs and accessory buildings
  • Small shops and single-room commercial spaces

True DIY Installation

The MRCOOL DIY Hyper Heat system uses factory-sealed, pre-charged QuickConnect® refrigerant lines. The line set is designed to connect without vacuuming, refrigerant charging, or specialized HVAC tools. Mount the indoor unit, place the outdoor condenser, connect the QuickConnect® line set, connect the DIYPRO® cable, and complete the required 208/230V electrical connection according to local code.

A licensed electrician is recommended for the electrical hookup. The refrigerant connection is DIY-friendly, but electricity remains annoyingly committed to hurting people who disrespect it.

Line Set Length Information

This system includes a standard 25 ft QuickConnect® pre-charged line set. Extended line set options may include an additional line set, couplers, and a longer control wire for installations that require more distance between the indoor air handler and outdoor condenser.

QuickConnect® line sets should not be cut. Any extra line set length should be properly coiled and installed according to MRCOOL installation guidelines.

Hyper Heat vs Standard DIY Mini Splits

Standard DIY mini split systems are excellent in mild and moderate climates, but many begin losing heating capacity when outdoor temperatures drop below freezing. The MRCOOL DIY Hyper Heat system is designed for colder regions and more demanding spaces where dependable winter heating matters.

The inverter-driven compressor, R-454B refrigerant, variable-speed outdoor fan, and electronic expansion valve help this system maintain stable heating operation down to -22°F. That makes it a smart choice for northern states, mountain towns, garage workshops, older homes without ductwork, and rooms that need year-round comfort.

Outdoor Condenser Performance Specifications

Specification Value
Outdoor Model DIYHH-12-HP-C-230D25-O
System Type Single-Zone Hyper Heat Mini Split
Cooling Capacity 12,000 BTU
Heating Capacity 12,000 BTU
Recommended Coverage Area Up to 550 sq. ft.
SEER2 23.5
EER2 12.8
HSPF2-4 10
HSPF2-5 8
Inverter Yes – DC Rotary Compressor
Minimum Heating Ambient Temperature -22°F
Minimum Cooling Ambient Temperature -22°F
Outdoor Noise Level 56.5 dB

Outdoor Condenser Electrical Specifications

Electrical Specification Value
Voltage 208/230V
Phase 1 Phase
Frequency 60 Hz
Minimum Circuit Ampacity 15 A
Maximum Fuse / Breaker 15 A
Dedicated Circuit Required Yes

Refrigeration & Piping Specifications

Refrigeration Specification Value
Refrigerant Type R-454B, Factory Pre-Charged
Included Line Set Length 25 ft QuickConnect®
Maximum Line Set Length 75 ft
Liquid Line Size 1/4 in.
Suction Line Size 3/8 in.
Field Vacuum Required No
Field Refrigerant Charging Required No

Indoor Wall-Mount Air Handler Specifications

Indoor Unit Specification Value
Indoor Model DIY-12-HP-WMAH-230D25-O
Indoor Unit Type Wall-Mounted Air Handler
Cooling / Heating Capacity 12,000 BTU
Recommended Room Size Up to 550 sq. ft.
Mounting Type Wall-Mounted
Voltage 208/230V, Powered from Outdoor Unit
Fan Speeds 5-Speed Fan
Sound Rating Approx. 19–54.5 dB
Operating Modes Cool, Heat, Auto, Dry, Fan, Sleep
Filter Reusable Washable Filter

Smart Control Features

Smart Feature Included
WiFi Enabled Yes
App Control MRCOOL SmartHVAC™ App for iOS and Android
Amazon Alexa® Voice Control Yes
Google Assistant® Voice Control Yes
Wireless Remote Control Included
Programmable Timer Yes
Auto Mode Yes
Sleep Mode Yes
Dry / Dehumidification Mode Yes

Warranty Coverage

Warranty Item Coverage
Compressor Warranty 7-Year Compressor Warranty with Registration
Parts Warranty 5-Year Parts Warranty with Registration
Extended Coverage Limited Lifetime Compressor Replacement Available with MRCOOL® Care Enrollment

Frequently Asked Questions

Do I need an HVAC technician to install this MRCOOL DIY Hyper Heat system?

The refrigerant line set connection is designed for DIY installation using MRCOOL QuickConnect® pre-charged line set technology. No vacuum pump, gauges, nitrogen, or field refrigerant handling are required. A qualified electrician is recommended for the required 208/230V electrical connection.

Can I mount the wall air handler myself?

Yes. The wall-mount bracket and mounting hardware are included. Always follow the installation manual for clearances, mounting height, drain routing, and line set routing.

Does this system heat well in winter?

Yes. This is a MRCOOL Hyper Heat system engineered for cold-climate heating operation down to -22°F.

Do I need a separate breaker for the indoor air handler?

No. The indoor wall-mounted air handler is powered from the outdoor unit. The outdoor condenser requires the dedicated 208/230V circuit. Always follow local electrical code and the installation manual.

Can this system be expanded later?

No. This is a single-zone mini split system and is designed to serve one indoor air handler. If you need to condition multiple rooms, choose a MRCOOL DIY multi-zone system instead.

What size room will this 12K Hyper Heat mini split cover?

This 12,000 BTU system is designed for spaces up to approximately 550 sq. ft. Actual sizing depends on insulation, ceiling height, layout, window exposure, climate zone, and other building conditions.

Does this bundle include the line set?

Yes. This complete bundle includes a 25 ft QuickConnect® pre-charged line set.

Can this system run on 115V power?

No. This is a 208/230V system and must not be connected to a 115V circuit or paired with 115V air handlers.

Why Buy From MRCOOL DIY Direct?

MRCOOL DIY Direct specializes in MRCOOL DIY systems, Hyper Heat mini splits, QuickConnect® line sets, accessories, parts, and support. Our team can help verify system sizing, electrical requirements, line set length, installation layout, and compatibility before you order.

Getting the right mini split the first time matters. Ordering the wrong voltage, wrong line set, or wrong system type is not “part of the adventure.” It is just expensive nonsense in a cardboard box.

Rated 4.7 / 5 Stars
4700+ Verified Reviews

Comfort That Speaks for Itself

See why homeowners and pros alike trust MRCOOL DIY systems to deliver comfort, savings, and easy installation.

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

I never thought I’d install my own HVAC system, but MRCOOL made it possible. The instructions were easy, and the pre-charged lines saved me from hiring a tech. Cools my garage workshop perfectly!

Jason R., North Carolina

Our MRCOOL mini-split runs really quiet — you can barely tell it’s on. Our electric bill dropped about 35% this summer. Very impressed with the efficiency

Megan L., Arizona

Installed this in my detached office. Took me a Saturday morning and a friend to lift the outdoor unit. Works flawlessly — heats in winter and cools in summer.

Daniel P., Texas

I swapped my old central unit for two MRCOOL DIY mini-splits. Same comfort, way lower bills. The inverter technology really makes a difference.

Jennifer C., Florida

Had a small question during installation and Vanessa picked up right away. They walked me through it step by step — best customer service I’ve had in years.

Chris B., Ohio

Keeps our sunroom comfortable in 100°F summers and comfy in the winter. The heat pump feature is amazing — one system for both heating and cooling!

Angela K., Kentucky

I’ve remodeled a few homes, and MRCOOL DIY systems are a game-changer. No need for HVAC pros or special tools — everything is plug-and-play.

Brandon S., Tennessee

Why Buy From Us

Why Buy from MRCOOL DIY Direct?

Trusted nationwide for MRCOOL DIY systems, support, and installation guidance.

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Top MRCOOL Dealer

Trusted nationwide for DIY mini split systems.

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DIY System Experts

Specializing in MRCOOL DIY systems and support.

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Fast Shipping

Quick delivery across the lower 48 states.

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Real Support

Help with sizing, compatibility, and installation.

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Family-Owned

Based in Missouri, serving nationwide.

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Complete System Guidance

We help you get everything needed for install.