MRCOOL DIYHH-18 Hyper Heat 18K BTU Condenser – 5th Gen, -22°F Heating, R-454B, 230V DIY QuickConnect

MRCOOL DIYHH-18 Hyper Heat 18K BTU Condenser with 25 ft QuickConnect® Line Set

The MRCOOL® DIYHH-18-HP-C-230D25-O Hyper Heat 18K BTU Condenser is a 5th Generation DIY outdoor mini split condenser designed for powerful year-round comfort, high-efficiency cooling, and true cold-climate heating performance down to -22°F. This 208/230V outdoor unit includes a 25 ft factory pre-charged R-454B QuickConnect® line set, making it a strong choice for homeowners who want a DIY-compatible mini split system without vacuum pumps, gauges, nitrogen, or field refrigerant handling.

This listing is for the outdoor condenser and 25 ft pre-charged line set only. A compatible MRCOOL DIY 230V indoor air handler or OuttaSight® ceiling cassette is required and sold separately.

Important: This is a 208/230V condenser. It cannot be used with 115V air handlers. Pair only with compatible MRCOOL DIY Hyper Heat 230V indoor units.

The 5th Gen DIY Hyper Heat Condenser Built for Real Winters

The MRCOOL DIYHH-18 Hyper Heat condenser is built on MRCOOL’s 5th Generation DIY platform and is engineered for reliable heating and cooling in demanding climates. With 21.2 SEER2, 11 HSPF2-4, inverter rotary compressor technology, and next-generation R-454B refrigerant, this condenser delivers efficient performance for bedrooms, garages, shops, cabins, bonus rooms, ADUs, offices, apartments, barndominiums, and other hard-to-condition spaces.

Unlike many standard mini split condensers that lose heating capacity as temperatures drop, the DIYHH-18 Hyper Heat condenser is designed to keep producing usable heat down to -22°F. So instead of watching a bargain system tap out the moment winter gets serious, this one keeps doing its job. Revolutionary concept, apparently.

What’s Included

• DIYHH-18-HP-C-230D25-O – MRCOOL Hyper Heat 18K Outdoor Condenser, 208/230V
• DIY25-1412 – 25 ft Pre-Charged R-454B QuickConnect® Line Set
• Installation Hardware
• Installation Documentation

Note: Indoor air handler, DIYPRO® communication cable, remote, and indoor mounting hardware are sold separately with the compatible indoor unit.

Compatible Indoor Units Sold Separately

• DIY-18-HP-WMAH-230D25-O – MRCOOL DIY Hyper Heat 18K Wall Mount Air Handler
• DIYCASSETTE18HP-230D25-O – MRCOOL DIY OuttaSight® 18K Ceiling Cassette

Both compatible indoor units connect using MRCOOL’s factory-sealed QuickConnect® fittings for DIY-friendly installation.

Key Features

• 18,000 BTU Hyper Heat outdoor condenser
• True cold-climate heating operation down to -22°F
• 5th Generation MRCOOL DIY platform
• Includes 25 ft factory pre-charged QuickConnect® line set
• Uses next-generation R-454B refrigerant
• No vacuum pump, gauges, or refrigerant charging required for line set connection
• 21.2 SEER2 high-efficiency cooling
• 11 HSPF2-4 heating efficiency
• Inverter rotary compressor for quiet, efficient operation
• Gold Fin® anti-corrosion condenser coating
• Compatible with MRCOOL DIY 230V wall mount air handler or OuttaSight® ceiling cassette
• SmartHVAC™ app, Amazon Alexa®, and Google Assistant® compatibility when paired with compatible indoor unit

Ideal Applications

• Garage mini split systems
• Detached workshops and shops
• Bonus rooms and additions
• Cabins and mountain homes
• Basements and finished lower levels
• Home offices and studios
• Barndominiums and pole barns
• Tiny homes and ADUs
• Apartments and rental properties
• Cold-climate single-zone mini split installations

Performance Specifications

Specification	Value
Outdoor Model	DIYHH-18-HP-C-230D25-O
System Type	Single-Zone Hyper Heat Outdoor Condenser
BTU Capacity	18,000 BTU
Recommended Coverage Area	Approx. 500–800 sq. ft.
SEER2	21.2
EER2	12.5
HSPF2-4	11
HSPF2-5	8.5
Minimum Heating Ambient Temperature	-22°F
Operating Temperature Range	-22°F to 122°F
Compressor Type	Inverter Rotary
Outdoor Airflow	1765.8 CFM
Sound Level	58 dBA

Electrical Specifications

Electrical Specification	Value
Voltage	208/230V
Phase	1 Phase
Frequency	60 Hz
Minimum Circuit Ampacity	19 A
Maximum Fuse / Breaker	25 A Double Pole
Dedicated Circuit Required	Yes

Refrigeration & Piping Specifications

Refrigeration Specification	Value
Refrigerant Type	R-454B
Factory Charge Volume	52.21 oz
Included Line Set	25 ft QuickConnect® Pre-Charged Line Set
Maximum Supported Line Set Length	75 ft
Liquid Line Size	1/4 in.
Suction Line Size	1/2 in.
Metering Device	Electronic Expansion Valve, EEV
Vacuum Pump Required	No
Field Refrigerant Charging Required	No

Dimensions & Weight

Dimension	Value
Unit Width	35.04 in.
Unit Height	26.50 in.
Unit Depth	13.46 in.
Unit Weight	99.87 lbs
Shipping Width	40.55 in.
Shipping Height	29.53 in.
Shipping Depth	18.11 in.
Shipping Weight	120.15 lbs

Line Set Information

This condenser includes a 25 ft pre-charged QuickConnect® line set. The line set is factory-sealed and designed to connect with compatible MRCOOL DIY indoor units without vacuuming or field refrigerant charging.

If your installation requires more distance between the indoor unit and outdoor condenser, verify compatibility with extended MRCOOL DIY line set options before ordering. The maximum supported line set length for this condenser is 75 ft.

Important Compatibility Notes

• This condenser is 208/230V only.
• This condenser is not compatible with 115V MRCOOL DIY air handlers.
• A compatible MRCOOL DIY 230V indoor unit is required and sold separately.
• The DIYPRO® cable is included with the compatible indoor unit, not this condenser-only listing.
• Smart control features require connection to a compatible MRCOOL DIY indoor unit.

Warranty Coverage

Warranty Item	Coverage
Compressor Warranty	7-Year Registered Compressor Warranty
Parts Warranty	5-Year Registered Parts Warranty
Extended Coverage	Eligible for Limited Lifetime Compressor Replacement with MRCOOL® Care Enrollment

Frequently Asked Questions

Does the MRCOOL DIYHH-18 condenser work in cold weather?

Yes. The MRCOOL DIYHH-18 Hyper Heat condenser is engineered for heating operation down to -22°F, making it a strong option for cold-climate mini split installations.

Can I install this condenser myself?

Yes. The included QuickConnect® line set is pre-charged and factory-sealed. The refrigerant line connection does not require a vacuum pump, gauges, nitrogen, or field refrigerant charging. A licensed electrician is recommended for the required 208/230V electrical connection.

What indoor units work with this condenser?

This condenser is compatible with the MRCOOL DIY-18-HP-WMAH-230D25-O wall mount air handler and the DIYCASSETTE18HP-230D25-O OuttaSight® ceiling cassette. Indoor units are sold separately.

Can I use this condenser with a 115V air handler?

No. This condenser is 208/230V only and must be paired with compatible MRCOOL DIY 230V indoor units.

What size space does an 18K BTU condenser cover?

An 18,000 BTU mini split typically covers approximately 500–800 sq. ft., depending on insulation, ceiling height, window exposure, layout, climate zone, and other building conditions.

Does this listing include the indoor air handler?

No. This listing includes the outdoor condenser and 25 ft pre-charged line set only. A compatible indoor air handler or ceiling cassette must be purchased separately.

Does this condenser include Wi-Fi or app control?

SmartHVAC™ app control, Amazon Alexa®, and Google Assistant® compatibility are available when this condenser is paired with a compatible MRCOOL DIY indoor unit.

Why Buy From MRCOOL DIY Direct?

MRCOOL DIY Direct specializes in MRCOOL DIY systems, components, bundles, and support. Our team can help verify compatibility between condensers, air handlers, ceiling cassettes, line sets, electrical requirements, and installation layout before you order.

This matters because buying individual mini split components without checking compatibility is how people accidentally create very expensive garage decorations. We would rather help you get the correct equipment the first time.