MRCOOL® DIY® 5th Gen - R454B - 12K Hyper Heat BTU 230v Condenser w/ 25ft Install Kit

Product Resource 

Introducing the New 2025  The MRCOOL DIYHH-12-HP-C-230D25-O is a next-generation 5th Gen Hyper Heat DIY condenser designed to deliver 12,000 BTU of high-efficiency heating and cooling in spaces up to 500 sq. ft. Built for true cold-weather performance, this Hyper Heat mini split maintains reliable output down to -22°F and uses inverter technology for quiet, steady comfort instead of loud single-stage cycling.

Powered by environmentally friendly R-454B refrigerant, the DIYHH-12 condenser increases thermal efficiency and reduces greenhouse impact compared to older R-410A systems. Installation is simple thanks to the 25-foot pre-charged Quick Connect® line set, which arrives sealed, factory-vacuumed, and filled—no gauges, pumps, nitrogen, or HVAC licensing required.

Whether paired with the DIY wall-mounted air handler or the OuttaSight® ceiling cassette, the system includes full smart control integration through the MRCOOL SmartHVAC app, Amazon Alexa, and Google Assistant. The DIYPRO®(is with the air handler) cable replaces electrical conduit to protect wiring from weather, pests, and accidental damage. With corrosion-resistant Gold Fin® construction, this condenser is engineered for long-term durability in both inland and coastal environments.

Bullet Feature List 

• Hyper Heat performance: Reliable heating down to -22°F
• 23.5 SEER2 & 10 HSPF2: Ultra-efficient year-round comfort
• R-454B Refrigerant: Lower GWP, next-generation eco solution
• DIY Quick Connect®: No vacuum pump, nitrogen, or special HVAC tools
• Gold Fin® Anti-Corrosion: Built for coastal and harsh climates
• Smart control: App, Wi-Fi, Alexa, Google Assistant
• OuttaSight® cassette compatible: Cleanest ceiling installation style
• Silent rotary inverter compressor: Smooth operation, low noise
• DIYPRO® cable included: Replaces conduit and protects wiring
• MRCOOL Care Kit program available

WORKS WITH:
✔ DIY-12-HP-WMAH-230D25-O Wall Mounted Air Handler
✔ DIYCASSETTE12HP-230D25-O OuttaSight® Ceiling Cassette

What's Included

✔ DIYHH-12-HP-C-230D25-O   DIY 5th Gen - R454B - 12K Hyper Heat BTU 230V Condenser.

✔ DIY25-1438-O   25ft 1/4 x 3/8 Line set for DIY 6K, 9K & 12K Indoor - R454B

Designed for everyday homeowners, rental properties, cabins, garages, bonus rooms, offices, and small commercial spaces, the DIYHH-12 delivers premium performance at a lower cost. With MRCOOL Care enrollment, users can access a care kit program, backed by the standard 7-year compressor and 5-year parts warranty. Experience year-round comfort with a system built for real-world conditions and DIY install confidence.

The MRCOOL DIYHH-12 Hyper Heat condenser delivers reliable 12K Hyper Heat performance for year-round comfort. As a DIY 5th Gen mini split system, it uses R-454B refrigerant for improved efficiency and lower environmental impact. Installation is simple because the pre-charged Quick Connect line set comes vacuum-sealed from the factory, making setup fast and clean without special tools. The corrosion-resistant Gold Fin condenser is ideal for long-term outdoor durability, whether installed inland or in coastal conditions. With full integration through the SmartHVAC app, the system offers control through smartphones, voice assistants, and built-in scheduling. Rated at 23.5 SEER2 AC and 10 HSPF2 heat, this single zone mini split is designed for efficient performance in spaces up to 500 sq ft and can be paired with either a wall mount air handler or an OuttaSight ceiling cassette. Engineered for harsh climates, it maintains dependable -22°F heating so you stay comfortable even during extreme cold weather.

SPECIFICATIONS

SEER2	23.5
EER2	12.8
HSPF2-4	10
HSPF2-5	8
CFM	1471.5
TONNAGE	1
COOLING CAPACITY (BTU)	12000
HEATING CAPACITY (BTU)	12000
VOLTAGE (V)	208/230
PHASE	1
CYCLE	60
MAX FUSE BREAKER (A)	15
MIN CIRCUIT AMPACITY (A)	15
COLOR	White
MAX COVERAGE AREA	500
REFRIGERANT TYPE	R-454B
REFRIGERANT VOLUME (OZ)	32.1
DECIBEL RATING (DBA)	56.5
INVERTER	Yes
MIN AMBIENT COOL (F)	-22
MIN AMBIENT HEAT (F)	-22
LINESET INCLUDED	Yes
LINE SET LENGTH	25ft
MAX LINESET LENGTH (FT)	75
LIQUID LINE SIZE	1/4
SUCTION LINE SIZE	3/8
COMPRESSOR MOTOR TYPE	Rotary
CONDENSER FAN MOTOR RPM	780/680/580
METERING DEVICE	EEV
ENERGY STAR CERTIFIED	Yes
AHRI CERTIFIED	Yes
REGISTERED WARRANTY	7-Years Compressor, 5-Years Parts
BASE WARRANTY	5-Years Parts
BASE PARTS WARRANTY	5 Years
BASE COMPRESSOR WARRANTY	7 Years
CONTAINS ELECTRONICS	Yes
CONTAINS CHEMICALS	Yes
CONTAINS COMPRESSED GAS	Yes
PROPOSITION 65 WARNING	Yes
RESTRICTED STATES	GU;PR;VI
NET DEPTH (IN)	12.99
NET HEIGHT (IN)	21.81
NET WIDTH (IN)	31.69
NET WEIGHT (LBS)	72.31

 All specifications are preliminary and are subject to change during mass production.

 

Frequently Asked Questions & Answers 

What's the difference between the 5th Gen and 4th Gen?

The 5th Gen MRCOOL® DIY® Mini Split offers several key upgrades over the 4th Gen, focusing on efficiency, advanced technology, and eco-friendliness.

Here’s what’s new with the 5th Gen:

• Next-Gen R-454B Refrigerant: A more environmentally friendly refrigerant with lower global warming potential (GWP), compliant with the latest HVAC regulations.
• Higher Energy Efficiency: Improved SEER2 ratings for greater energy savings and optimized performance.
• Enhanced System Reliability: Upgraded components for better heating and cooling performance.
  
  

Can I install it myself, or do I need a professional?

The MRCOOL® DIY system is designed for homeowners and doesn’t require HVAC tools. You can install the indoor and outdoor units yourself using the pre-charged Quick Connect® lines. However, a licensed electrician is required for the electrical hookup to ensure safety and code compliance.

Does it work in cold weather?

Yes. MRCOOL® 5th Gen systems feature low-ambient heating and can provide reliable heat even when outdoor temperatures drop to around 5°F.

How do I know what BTU size I need for my rooms?

A general rule of thumb is 20 BTU per square foot of space. Here's a rough guide:

• 6,000 BTU = 100 - 200sq ft
• 9,000 BTU = 150 - 400sq ft
• 12,000 BTU = 351- 550 sq ft
• 18,000 BTU = 501 – 800 sq ft
• 24,000 BTU = 751 – 1,050 sq ft
• 36,000 BTU = 1,001 - 1,550 sq ft

Some additional factors may impact performance such as insulation, ceiling height, sun exposure and the number of appliances in the room. For assistance, contact our Product Experts.

Does it heat as well as cool?
Yes. All 5th Gen models are heat pumps, providing both heating and cooling for year-round comfort.

Is it Wi-Fi compatible?

Yes. The MRCOOL® SmartHVAC app allows smartphone control and works with Amazon Alexa and Google Assistant.

What is the warranty?

The MRCOOL® 5th Generation DIY Mini-Split systems offer the following warranty coverage:

• 7-Year Compressor Replacement Warranty: This warranty ensures that if the compressor fails within the first seven years, MRCOOL® will provide a replacement.
• 5-Year Parts Warranty: This warranty covers all parts of the system for five years from the date of purchase.

Note: Always verify system configuration before purchasing. Specifications may change during production. Images may be representative only.

 

Featuring EEV metering technology, a rotary inverter compressor, 1/4–3/8 QuickConnect lines, and 32.1 oz factory pre-charge, the DIYHH-12 maintains stable system pressures while maximizing coil utilization. AHRI Certified and Energy Star rated.