What's in the box
- 1 × MRCOOL® DIY® Hyper Heat 18K BTU Condenser
- 1 × MRCOOL® DIY® 18K BTU 5th Gen Wall-Mounted Air Handler
- 1 × 25 ft QuickConnect® Line Set (1/4" × 1/2")
- 1 × MRCOOL® Remote Control
- 1 × DIYPRO® Cable
- Designed for simplified installation using MRCOOL® QuickConnect® technology
- No vacuum pump or specialized HVAC equipment required
- Local electrical requirements and building codes may vary
- Professional electrical work may still be recommended depending on local regulations
- Always review the installation manual before purchase and installation
- 7-Year Compressor Warranty
- 5-Year Parts Warranty
Please refer to the Warranty Document above for full coverage details, terms, and registration requirements.
- Free standard shipping is available on eligible orders to the Lower 48 states and Washington, D.C.
- Orders are generally processed within 3–5 business days, followed by approximately 5–12 business days in transit.
- Smaller items may ship by parcel carrier. Larger equipment may be delivered curbside by freight carrier, and the carrier may contact you to coordinate delivery.
- Return requests may be submitted within 30 calendar days of delivery. Products must be new, unused, uninstalled, complete and in their original manufacturer packaging. Powered products must not have been energized.
- For approved change-of-mind, incorrect-sizing or customer-ordering-error returns, the customer is responsible for return freight and a 15% restocking fee. Verified damaged, defective, incorrect or incomplete orders are handled separately.
View our Shipping Policy and Returns & Warranty Policy.
Manuals & documents
MODEL: DIYHH-18-HP-WM-230D25-O
Built for Winter.
Extreme Cold Heating. Powerful Cooling. DIY Simple.
Still worried your home won't stay warm when temperatures plunge?
The MRCOOL® DIY® Hyper Heat 18K BTU Mini Split System was built for homeowners who refuse to let winter dictate their comfort. While many heating systems struggle in extreme cold, Hyper Heat technology continues delivering reliable heating in temperatures as low as -22°F, helping keep your space warm, comfortable, and energy efficient when you need it most.
Perfect for living rooms, large bedrooms, home offices, cabins, basements, workshops, and other spaces up to 800 sq ft, this complete system combines a MRCOOL® DIY® Hyper Heat Condenser and a MRCOOL® DIY® 18K 5th Generation Wall-Mounted Air Handler to provide dependable heating, cooling, and year-round comfort. The included 25 ft QuickConnect® line set comes pre-charged with environmentally friendly R-454B refrigerant, helping simplify installation without specialized HVAC tools.
Advanced DC inverter technology, impressive 21.2 SEER2 efficiency, SmartHVAC® app control, Amazon Alexa®, Google Assistant®, and the included DIYPRO® cable give you complete control, outstanding efficiency, and dependable comfort in every season.
Whether it's a freezing winter morning or the hottest day of summer, Hyper Heat delivers the confidence of knowing your comfort system is ready.
Warm when others struggle. Cool when others quit. Built for extreme climates.
Why You'll Love It
✅ Reliable heating in temperatures as low as -22°F
✅ Ideal for spaces between 550–800 sq ft
✅ High-efficiency 21.2 SEER2 performance
✅ Simplified DIY installation with QuickConnect® technology
✅ SmartHVAC® app control from anywhere
✅ Compatible with Amazon Alexa® & Google Assistant®
✅ Gold Fin® corrosion-resistant condenser protection
✅ Includes 25 ft pre-charged QuickConnect® line set
✅ Energy-saving DC inverter technology
Best For
Living Rooms • Large Bedrooms • Home Offices • Cabins • Basements • Workshops • Studios • Cold Climate Homes
Need More Heating & Cooling Power?
Explore larger systems for bigger spaces or higher heating and cooling demands:
| Coverage Area | 550–800 sq ft |
| Cooling Capacity | 18,000 BTU |
| Heating Capacity | 18,000 BTU |
| Voltage | 208/230V |
| Zone Type | Single Zone |
| SEER2 | 21.2 |
| EER2 | 12.5 |
| HSPF2-4 | 11.0 |
| HSPF2-5 | 8.5 |
| Refrigerant | R-454B |
| Inverter Technology | DC Inverter |
| Compressor Type | Rotary |
| Sound Level (Outdoor) | 58 dB(A) |
| Minimum Cooling Temperature | -22°F |
| Minimum Heating Temperature | -22°F |
| WiFi Compatible | Yes |
| Voice Control | Alexa® & Google Assistant® |
| Line Set Length | 25 ft |
| Maximum Line Set Length | 75 ft |
| Line Sizes | 1/4" Liquid / 1/2" Suction |
| Certifications | ENERGY STAR®, AHRI, ETL, UL, CSA |
| Warranty | 7-Year Compressor / 5-Year Parts |
Questions, answered
Everything homeowners ask before buying a MRCOOL® system.
Installation
What installation requirements apply to this product?
Installation requirements vary by product type. Selected complete MRCOOL® DIY systems are designed for homeowner installation when fitted in line with the manufacturer’s instructions, local codes and permit requirements.
Central HVAC systems, including Universal®, VersaPro®, Central Ducted Hyper Heat and packaged systems, are intended for professional installation by a qualified HVAC contractor. Licensed electrical work may also be required.
Components, thermostats, controls, line sets and accessories should be installed according to their product documentation and compatibility requirements. Always review the product page, manufacturer guidance and warranty conditions before installation.
Will I need any additional parts, tools or professional services?
Additional requirements vary by product and installation. Tools, electrical materials, mounting hardware, connecting components or other installation supplies may be required unless specifically stated as included.
Review the product description, specifications, installation information and What’s Included section, where available, before ordering.
Where can I find product documents or installation instructions?
Available specifications, installation instructions, owner’s manuals and manufacturer documents are provided on the product page where applicable.
Some simple accessories may not have a separate installation manual. Contact our team if you need help locating documentation for a particular product or model.
Sizing & Compatibility
How do I confirm this product is compatible with my equipment?
Review the product type, model number, dimensions, voltage, capacity, refrigerant type, connection sizes and compatibility information shown on the product page, where applicable.
Components, thermostats, controls and accessories must be matched to compatible equipment. Contact our team before ordering if you are uncertain about compatibility.
What should I check before ordering?
Confirm the product name and model number, together with any relevant dimensions, voltage, capacity, refrigerant type, connections and installation requirements.
For replacement components and accessories, compare the product specifications with your existing equipment and the relevant manufacturer documentation before placing your order.
What is included with this product?
The supplied items are listed in the What’s Included section or product description, where applicable. Only the products, components and accessories specifically stated are included.
Electrical materials, mounting equipment, connecting components or other installation supplies may need to be purchased separately unless expressly stated otherwise.
Warranty & Support
What warranty coverage applies to this product?
Warranty coverage varies by product and model. Eligible MRCOOL® products are covered according to the manufacturer’s warranty terms, registration requirements and installation conditions.
Accessories and individual components may have different coverage. Cool Heat Direct can provide available warranty documentation and general guidance, while warranty eligibility and claim decisions are determined by the manufacturer.
How can I get help before ordering?
Email support@coolheatdirect.com with the product name or model number and details about your project or existing equipment.
For compatibility questions, include the model numbers of any products you intend to connect, control, replace or use together.
Support hours: Monday–Friday, 9 AM–6 PM ET.
Shipping & Returns
How will my order be shipped?
Free standard shipping is available on eligible orders to the Lower 48 states and Washington, D.C.
Orders are generally processed within 3–5 business days, followed by approximately 5–12 business days in transit. Delivery timing varies by product availability, destination and carrier scheduling.
Smaller products may ship by parcel carrier. Larger equipment may be delivered curbside by freight carrier. The carrier may contact you to arrange a delivery appointment.
Can I return this product?
Return requests may be submitted within 30 calendar days of delivery. Products must be new, unused and uninstalled and, where applicable, unpowered. They must also be complete and in their original manufacturer packaging. Prior written authorization is required.
For approved change-of-mind returns, incorrect sizing or customer ordering errors, the customer is responsible for return freight and a 15% restocking fee applies.
Verified damaged, defective, incorrect or incomplete orders are handled separately under our full policy.
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