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Home DIY 5th Gen Hyper Heat Series
DIY 5th Gen Hyper Heat Series

MRCOOL DIY 5th Gen Hyper Heat 18K BTU Single Zone Mini Split System 230V, DIYHH-18-HP-WM-230D25-O

SKU DIYHH-18-HP-WM-230D25-O Wall Mount21.2 SEER2208-230V
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$3,173.00
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High efficiency. Quiet performance. Easy installation.

A smart, reliable choice for year-round comfort.

Best for:
  • Bedrooms
  • Home Offices
  • Additions
  • Garages
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Cooling
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Heating
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Quiet Inside
High
High Efficiency

Brand Information

MrCool
Support Number
(270)366-0457
Product Overview Full product description Read the longer product copy, features, and application notes.
MRCOOL — DIY Hyper Heat (5th Gen)

MRCOOL® DIY 18K Hyper Heat 5th Gen Mini Split System

Summary

The MRCOOL® DIYHH-18 Hyper Heat 18K Mini Split Systemis a 5th Generation Hyper Heat bundle engineered for cold-climate performance down to-22°Fwith genuine DIY installation. This complete system delivers18,000 BTUheating and cooling for spaces up to800 sq. ft., combining professional capability with homeowner-friendly setup.

Featuring theDIYHH-18-HP-C-230D25-Ooutdoor condenser andDIY-18-HP-WMAH-230D25-Owall-mounted air handler, this system uses factory-sealed QuickConnect® pre-charged line sets withR-454Brefrigerant—eliminating the need for vacuum pumps, gauges, or HVAC certification. With efficiency ratings of21.2 SEER2and11 HSPF2-4, smart controls via the MRCOOL SmartHVAC App, and Alexa/Google compatibility, it’s a strong fit for garages, additions, workshops, and larger rooms.

Highlights

18,000 BTU Hyper Heat to -22°F 21.2 SEER2 11 HSPF2-4 25 ft QuickConnect® R-454B WiFi + Voice
Coverage
Up to 800 sq. ft.
Voltage
208/230V
Breaker
25A max
Heat
Down to -22°F
  • 2025 5th Generation Hyper Heat:Enhanced cold-climate heating performance down to -22°F.
  • True DIY installation:Pre-charged QuickConnect® line set requires no vacuum pump, gauges, or refrigerant handling.
  • Premium efficiency:21.2 SEER2 and 11 HSPF2-4 ratings for reduced energy use.
  • Smart connectivity:MRCOOL SmartHVAC App + Alexa/Google Assistant + included remote.
  • Quiet indoor operation:Indoor sound levels as low as 19 dB.

What's Included

  • Outdoor Condenser:MRCOOL® DIYHH-18 Hyper Heat Condenser (DIYHH-18-HP-C-230D25-O)
  • Indoor Unit:MRCOOL® DIY-18 Wall Mount Air Handler (DIY-18-HP-WMAH-230D25-O)
  • Line Set:25 ft Pre-Charged QuickConnect® Line Set (DIY25-1412)
  • DIYPRO® Communication Cable
  • Wireless Remote Control
  • Complete mounting hardware & template
  • Installation and user manuals

Warranty

  • 7-Year Compressor Warranty (registration required)
  • 5-Year Parts Warranty (registration required)
  • Extended limited coverage with MRCOOL® Care

Important:Warranty benefits require product registration. Refer to MRCOOL warranty documentation for full terms and conditions.

Technical Information

Outdoor Model: DIYHH-18-HP-C-230D25-O

Brand MRCOOL
Series DIY Hyper Heat 5th Gen
Model DIYHH-18-HP-C-230D25-O
Unit Type Mini-Split
Equipment Type Condenser
Short Description 18K Hyper Heat 230V Condenser with QuickConnect®
Cooling Capacity (BTU) 18,000
Heating Capacity (BTU) 18,000
SEER2 21.2
EER2 12.5
HSPF2-4 11
HSPF2-5 8.5
Voltage 208/230
Phase 1
Cycle 60 Hz
Min Circuit Ampacity (A) 19
Max Fuse / Breaker (A) 25
Min Ambient Heat (°F) -22°F
Max Ambient Cool (°F) 122°F
CFM 1765.8
Compressor Type Inverter Rotary
Metering Device Electronic Expansion Valve (EEV)
Refrigerant Type R-454B
Refrigerant Volume (oz) 52.21 oz
Line Set Included Yes
Line Set Length 25 ft
Max Lineset Length (ft) 75 ft
Liquid Line Size 1/4"
Suction Line Size 1/2"
Decibel Rating High (dBA) 58
Net Width (in) 35.04
Net Height (in) 26.5
Net Depth (in) 13.46
Net Weight (lbs) 99.87

Indoor Model: DIY-18-HP-WMAH-230D25-O

Brand MRCOOL
Series DIY 5th Gen
Model DIY-18-HP-WMAH-230D25-O
Unit Type Mini-Split
Equipment Type Air Handler
Short Description 18K 230V Wall Mount Air Handler
Cooling Capacity (BTU) 18,000
Heating Capacity (BTU) 18,000
Max Coverage Area 800 sq. ft.
Mount Type Wall
Fan Speeds 5-Speed
Quiet Mode Yes
Decibel Rating Low (dBA) 19
Decibel Rating High (dBA) 54.5
Net Width (in) 42.52
Net Height (in) 13.19
Net Depth (in) 8.9
Net Weight (lbs) 35.49
Smart Features MRCOOL SmartHVAC App, Alexa, Google Assistant, Wireless Remote

Frequently Asked Questions

Is this system really DIY-friendly?

Yes. The pre-charged, factory-sealed QuickConnect® line set eliminates the most complex steps of traditional mini-split installation. No vacuum pump, gauges, or refrigerant handling is required.

How low of a temperature can it heat?

This Hyper Heat system is engineered to provide effective heating down to-22°Foutdoor temperature.

What electrical requirements are needed?

A dedicated208/230Vcircuit is required with a25Abreaker (19A minimum circuit ampacity).

Is the line set included?

Yes, a25 ftpre-charged QuickConnect® line set (DIY25-1412) is included. Extended lengths may be available.

Does it come with smart controls?

Yes. The system is WiFi-enabled for the MRCOOL SmartHVAC App and supports voice control with Amazon Alexa and Google Assistant.

Specs & Documents Product details Open technical specs, manuals, videos, and product documents.

Technical Data

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Product FAQs

Product FAQs

Helpful answers matched to this product, brand, specs, and configuration.
Where should I purchase MRCOOL equipment?

MRCOOL products are sold through authorized retailers and distributors rather than directly by MRCOOL to consumers. Purchasing through an authorized seller helps confirm that the equipment is genuine and that the correct purchase records are available for product and warranty support.

Can MRCOOL components from different series, generations, or refrigerant platforms be mixed?

Do not assume that MRCOOL indoor units, outdoor units, line sets, controls, or accessories are interchangeable. Use only manufacturer-approved combinations for the exact model family; in particular, MRCOOL states that R-410A products are not compatible with R-454B products and the refrigerants must never be mixed.

What makes an eligible MRCOOL DIY system different from a conventional mini-split?

Eligible MRCOOL DIY systems are designed around installation-friendly components such as factory-precharged line sets and compatible connection hardware. The included components vary by generation and package, and electrical work, permits, clearances, and local code requirements still need to be followed.

Does MRCOOL send technicians to a home or jobsite?

MRCOOL does not dispatch field technicians. Its in-house team provides phone and email assistance for diagnosis, troubleshooting, and product guidance, while the owner arranges and pays for any local on-site technician unless a specific written warranty program states otherwise.

Why do I need the exact MRCOOL model and serial number?

The model and serial number identify the exact equipment, generation, capacity, and applicable documentation or warranty. Use the identification labels on the equipment and MRCOOL’s registration guidance rather than relying only on a product title or general series name.

Are all MRCOOL systems designed for do-it-yourself installation?

No. Only product families specifically identified by MRCOOL as DIY-capable should be treated as do-it-yourself systems. Other lines, including the Advantage Series, require professional HVAC installation, so always follow the installation requirements for the exact model.

Where can I find MRCOOL manuals, specifications, certifications, and installation documents?

MRCOOL maintains a documentation library and a product support center with model-specific installation manuals, owner manuals, technical documents, certifications, warranty information, and troubleshooting resources. Search using the exact model number because documents can differ by series, generation, capacity, and refrigerant.

What types of products does MRCOOL offer?

MRCOOL offers a broad range of comfort products, including ductless mini-splits, central ducted split systems, packaged heat pumps, geothermal systems, water heaters, fans, thermostats, line sets, and HVAC accessories. Available capacities, refrigerants, efficiencies, and features depend on the exact product family and model.

When should an MRCOOL system be registered?

Register the system as soon as possible after purchase and installation. Several MRCOOL residential warranty programs require registration within 60 days of installation, or within 60 days of purchase when the installation date cannot be verified, but the exact requirement is controlled by the warranty document for the specific product.

Where can I purchase replacement parts for an MRCOOL system?

MRCOOL recommends starting with the original place of purchase because many dealers can special-order replacement parts. If that is not available, use an authorized MRCOOL parts distributor and confirm compatibility with the exact model and serial number before ordering.

How can I contact MRCOOL customer or technical support?

MRCOOL provides support by phone at (270) 366-0457, by email at support@mrcool.com, and through its online support-request form. Have the exact model and serial number available so the support team can identify the correct product documentation and next steps.

Can MRCOOL support work with my local HVAC technician?

Yes. If a local technician is scheduled, MRCOOL’s in-house support team can help coordinate troubleshooting and product guidance with that technician. The technician should have the model, serial number, system configuration, measurements, error codes, and a clear description of the issue available.

Where can I find MRCOOL troubleshooting and error-code information?

MRCOOL’s support center provides separate technical-support sections for ductless systems, residential ducted systems, product-specific error codes, wiring guidance, installation procedures, and troubleshooting articles. Use the exact series and model because codes and procedures are not universal across all MRCOOL equipment.

How do I register an MRCOOL product for warranty coverage?

Register the product through MRCOOL’s online warranty-registration page. Be prepared to provide the serial number along with purchase, owner, installation-location, and installer information requested by the registration form.

Does every MRCOOL product have the same warranty?

No. MRCOOL publishes separate warranty terms for different product families, generations, and applications. For example, the current DIY 5th Generation warranty lists 5-year parts and 7-year compressor coverage, but that coverage should not be assumed for another MRCOOL series; always check the exact product warranty document.

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