What's in the box
- 1 × MRCOOL® DIY® 18K 5th Gen Condenser — DIY-18-HP-C-230D25-O
- 1 × MRCOOL® DIY® 18K 5th Gen Air Handler — DIY-18-HP-WMAH-230D25-O
- 1 × 25 ft Quick Connect® Line Set, 1/4" × 1/2"
- 1 × MRCOOL® Remote Control
- 1 × DIYPRO® Cable
- Installation documentation
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Designed for simplified installation using MRCOOL® Quick Connect® technology.
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Local electrical requirements and building codes may vary.
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Professional electrical work may still be recommended depending on local regulations and installation requirements.
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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: DIY-18-HP-WM-230D25-O
More Power. Bigger Spaces. DIY Simple.
The MRCOOL® DIY® 5th Gen 18K BTU Single-Zone Mini-Split System (208/230V) delivers quiet, energy-efficient heating and cooling for spaces up to approximately 800 sq ft — all in one complete system designed for reliable year-round comfort.
Ideal for living rooms, larger bedrooms, garages, basements, open-plan spaces, home offices, and medium-to-large living areas, this system combines dependable performance, smart control, and simplified installation in one streamlined solution built for everyday use.
The system includes a wall-mounted indoor air handler, outdoor condenser, 25 ft Quick Connect® pre-charged line set with R-454B refrigerant, and DIYPRO® cable.
Control your comfort from anywhere using the SmartHVAC app on Apple or Android devices, or enjoy hands-free voice control with Amazon Alexa and Google Assistant.
Why You’ll Love It
✅ Ideal for spaces up to ~ 800 sq ft
✅ Heating & cooling in one complete system
✅ Smart app control with Alexa & Google Assistant
✅ Quiet performance for living spaces and larger rooms
✅ 25 ft Quick Connect® pre-charged line set included
✅ Energy-efficient DC inverter technology
✅ Gold Fin® coating for added durability
Best For
Living Rooms • Large Bedrooms • Garages • Basements • Open-Plan Spaces • Home Offices
Need More Heating & Cooling Power?
Explore larger systems for bigger spaces or higher heating and cooling demands:
| Specification | Details |
|---|---|
| Coverage Area | Up to 800 sq ft |
| Cooling Capacity | 18,000 BTU |
| Heating Capacity | 18,000 BTU |
| Voltage | 208/230V |
| Zone Type | Single Zone |
| SEER2 | 22.5 |
| EER2 | 13.7 |
| HSPF2-4 | 11.5 |
| HSPF2-5 | 8.5 |
| Indoor Sound Level | 19–54.5 dB(A) |
| Outdoor Sound Level | 58.5 dB(A) |
| WiFi Compatible | Yes |
| Voice Assistant | Alexa & Google Assistant |
| Inverter Technology | DC Inverter |
| Refrigerant | R-454B |
| Refrigerant Volume | 44.8 oz |
| Line Set Length | 25 ft |
| Max Line Set Length | 98.4 ft |
| Line Sizes | 1/4" Liquid / 1/2" Suction |
| Compressor Type | Rotary |
| Certifications | AHRI, UL, ETL, Energy Star® |
| 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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