Introducing what’s  New 2025 This is the first official MRCOOL 5th Gen DIY Hyper Heat 18K Mini split system available direct to consumer, engineered specifically for installs down to -22°F.

The MRCOOL DIYHH-18 Hyper Heat 18K bundle combines the DIYHH-18 condenser and the DIY-18-HP-WMAH-230D25-O wall mount air handler into a complete single zone system designed specifically for true homeowner installation. HVAC buyers search for diyhh-18, diy hyper heat 18k, mr cool  18k outside unit, and 5th gen diy condenser because this system is the first DIY Hyper Heat solution capable of maintaining real -22°F heating performance without professional tools, gauges, vacuum pumps, or refrigerant handling. This bundle delivers genuine contractor-grade results with factory-sealed QuickConnect® R-454B line sets, inverter technology, and seamless smart control.

WORKS WITH:
✔ DIY-18-HP-WMAH-230D25-O Wall Mount Air Handler
✔ DIYCASSETTE18HP-230D25-O OuttaSight® Ceiling Cassette

Long Description 

The MRCOOL DIYHH-18 Hyper Heat 18K bundle delivers powerful year-round comfort with true DIY installation. This 5th Generation system includes the DIYHH-18 condenser and the DIY-18-HP-WMAH-230D25-O wall mount air handler, providing a complete single zone solution that heats and cools spaces up to 800 sq. ft. Built specifically for harsh climate performance, the Hyper Heat inverter maintains dependable output down to -22°F and prevents the temperature swings associated with conventional single-stage systems.

Unlike standard mini split packages, this system uses factory-sealed QuickConnect® technology. The 25 ft line set arrives vacuumed, fully charged with R-454B refrigerant, and completely sealed—no vacuum pump, nitrogen, refrigerant gauges, recovery equipment, licensed installers, or EPA certification required. The included DIYPRO® cable eliminates the need for electrical conduit and protects against moisture, animals, yard equipment, and environmental wear.

Both the condenser and air handler are engineered for long-term performance. The Gold Fin® anti-corrosion coating resists coastal salt exposure and seasonal moisture. The inverter compressor quietly modulates output for comfort and efficiency, while the electronic expansion valve ensures stability and fast response. Users can control the system through the SmartHVAC™ app, voice assistants like Alexa or Google Assistant, or the included wireless remote.

With MRCOOL Care enrollment, customers can access a limited lifetime unit replacement program. Standard coverage includes a 7-year compressor warranty and 5-year parts warranty when properly registered. The DIYHH-18 bundle is ideal for bedrooms, living areas, basements, garages, workshops, home offices, and rental properties where professional installation is costly or impractical.

INCLUDES IN THIS COMPLETE DIY BUNDLE:
✔ DIYHH-18-HP-C-230D25-O – Hyper Heat 18K Outdoor Condenser (R-454B)
✔ DIY-18-HP-WMAH-230D25-O – 18K Wall-Mounted Air Handler
✔ DIY25-1412 – 25ft Pre-Charged QuickConnect® Line Set
✔ DIYPRO® Communication Cable

BULLET FEATURES

• Hyper Heat heating down to -22°F
• 21.2 SEER2 cooling / 11 HSPF2 heating
• R-454B low-GWP refrigerant
• 25 ft factory-charged QuickConnect® line set
• DIYPRO® cable – no conduit required
• SmartHVAC™ app, Alexa & Google Assistant
• Energy Star & AHRI Certified
• Gold Fin® outdoor corrosion protection
• Quiet inverter rotary compressor
• Eligible for MRCOOL Care lifetime replacement