MRCOOL DIY® 18,000 BTU 5th Gen Mini-Split Complete System 230V – Single Zone, Up to 750 Sq. Ft. | DIY-18-HP-WM-230D25-O
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MRCOOL DIY® 5th Gen E Star 18,000 BTU Single Zone Mini Split Complete System
Take control of your home comfort with the MRCOOL DIY® 5th Gen 18,000 BTU Single Zone Mini Split — America's #1 DIY mini split system. Designed for rooms between 500 and 750 sq. ft., this ENERGY STAR® certified system delivers powerful, year-round heating and cooling without the cost or hassle of professional installation. Everything you need is included: a 25 ft. QuickConnect® line set, DIYPRO® cable, and multiple wireless control options.
Why Choose MRCOOL DIY® 5th Gen?
- America's #1 DIY Mini Split — The most trusted DIY mini split brand in the nation, built for quick setup and long-term reliability.
- DIY QuickConnect® Line Set — Pre-charged with eco-friendly R-454B refrigerant for a fast, vacuum-free installation — no special tools needed.
- Eco-Friendly R-454B Refrigerant — Lower Global Warming Potential (GWP) than R-410A, delivering better energy efficiency with a reduced environmental footprint.
- DIYPRO® Cable — Eliminates the need for electrical conduit. Built tough to withstand outdoor elements and wildlife for lasting performance.
- Multiple Wireless Control Options — Control via included remote, the SmartHVAC app (iOS & Android), or hands-free with Amazon Alexa or Google Assistant.
- Follow Me Function — Airflow automatically adjusts based on the remote's location for consistent, even temperature throughout the room.
- Dry Mode — Works as a dehumidifier to reduce excess moisture and improve indoor air quality.
- Gold Fin® Condenser Coating — Superior corrosion resistance, ideal for coastal homes and harsh climates.
- Industry-Leading Warranty — 7-year compressor warranty + 5-year parts warranty for total peace of mind.
- Certified Excellence — UL Listed, ETL Listed, ENERGY STAR Certified, AHRI Certified.
Product Overview
- 🏠 Zones: 1
- 📐 Coverage: 500–750 sq ft.
- 🔧 Installation: DIY — No professional HVAC technician required
- ⚡ Voltage: 208-230V
- ⭐ ENERGY STAR Certified for maximum efficiency
Control your comfort from anywhere using the SmartHVAC app, remote control, Amazon Alexa, or Google Assistant. The Follow Me® function intelligently adjusts airflow based on your location for personalized comfort throughout the room.
The Gold Fin® condenser coating resists corrosion and extends system life, even in coastal or humid environments. Dry Mode helps reduce indoor humidity for improved comfort and air quality. Backed by a 7-year compressor warranty and 5-year parts warranty, this system is built to last.
What's Included
- ✅ 18K BTU Condenser — MRCOOL DIY® 5th Gen E Star Single Zone Mini Split Condenser 230V (Model: DIY-18-HP-C-230D25-O) × 1
- ✅ 18K BTU Air Handler — MRCOOL DIY® 5th Gen E Star Single Zone Mini Split Air Handler 230V with DIYPRO Cable (Model: DIY-18-HP-WMAH-230D25-O) × 1
- ✅ 25 ft. 1/4" x 1/2" Pre-Charged QuickConnect® Line Set — R-454B refrigerant, compatible with 18K indoor units × 1
Specifications & Dimensions
Dimensions & Weight
| Condenser Dimensions | 35.04"W x 13.46"D x 26.50"H |
| Air Handler Dimensions | 42.52"W x 8.90"D x 13.19"H |
| Condenser Weight | 93.48 lbs / 42.4 kg |
| Air Handler Weight | 35.49 lbs / 16.1 kg |
Capacity & Performance
| Zone Capacity | 1 |
| Cooling Capacity | 18,000 BTU |
| Outdoor Operating Temp (Cooling) | -13°F to 122°F |
| EER2 | 13.7 |
| SEER2 | 22.5 |
| Heating Capacity | 18,000 BTU |
| Outdoor Operating Temp (Heating) | -13°F to 75°F |
| HSPF2-4 | 11.5 |
| HSPF2-5 | 8.5 |
| Coverage Area | 500–750 sq ft. |
| Outdoor Noise Level | 58.5 dB(A) |
| Indoor Noise Level (Hi/Mi/Lo) | 54.5 / 44.5 / 40.5 / 30.5 / 19.0 dB(A) |
Electrical Requirements
| Voltage | 208-230V |
| Phase | 1 |
| Cycle | 60 Hz |
| Max Fuse/Breaker | 20A |
| Min Circuit Ampacity | 18A |
Refrigerant & Piping
| Refrigerant Type | R-454B |
| Refrigerant Volume | 44.80 oz |
| Liquid Line Size | 1/4" |
| Suction Line Size | 1/2" |
| Max Line Set Length | 98.4 ft. |
Features
| Inverter | DC |
| Compressor Type | Rotary |
| Fan Only Option | Yes |
| Quiet Mode | Yes |
| Auto Cool | Yes |
| WiFi Compatible | Yes |
| App Compatible | Yes (iOS & Android) |
| Remote Control Included | Yes |
Certifications & Warranty
| Certifications | UL Listed, ETL Listed, ENERGY STAR Certified, AHRI Certified |
| Compressor Warranty | 7 Years |
| Parts Warranty | 5 Years |
Installation & Guides
- 📄 Product Brochure (PDF)
- 📄 Quick Start Guide (PDF)
- 📄 Installation Manual (PDF)
- 📄 Service Manual (PDF)
- 📄 Remote Manual (PDF)
- 📄 Warranty (PDF)
Shipping & Returns
🚚 Free Curbside Delivery
All MRCOOL orders ship free via FedEx Ground, FedEx Freight, or an equivalent trusted carrier. Delivery is curbside only — please arrange assistance in advance as carriers are not able to bring items inside your home.
Tracking & Delivery
Tracking information is typically provided within 3–5 business days of your order. Once received, please allow 1–2 business days for tracking details to update.
↩️ Return Policy
30-Day Return Window: Returns must be requested within 30 days of your delivery date. We are unable to accept return requests after this period.
Return Conditions: To qualify for a return, items must be unused and uninstalled, and in original packaging including box and pallet.
Restocking Fee: A 35% restocking fee applies to all approved returns.
📄 View Full Shipping Policy | 📄 View Full Return & Refund Policy
Frequently Asked Questions
What's the difference between the 5th Gen and 4th Gen?
The 5th Gen MRCOOL DIY® is a meaningful upgrade over the 4th Gen in three key areas: it uses next-generation R-454B refrigerant (more eco-friendly with a lower global warming potential), achieves higher energy efficiency with improved SEER2 ratings, and features enhanced components for greater reliability and long-term performance.
Can I install it myself, or do I need a professional?
Yes — that's the whole point of the MRCOOL DIY® system. No HVAC tools or certification required. Simply connect the indoor and outdoor units using the pre-charged QuickConnect® line set. The only professional you'll need is a licensed electrician for the electrical hookup to ensure safety and local code compliance.
Does it work in cold weather?
Absolutely. The 5th Gen features low-ambient heating technology and delivers reliable heat even when outdoor temperatures drop to around 5°F — making it a true year-round comfort solution.
What BTU size do I need?
A general rule of thumb is 20 BTU per square foot. Here's a quick sizing guide:
- 6,000 BTU → 100–150 sq ft
- 9,000 BTU → 150–350 sq ft
- 12,000 BTU → 351–500 sq ft
- 18,000 BTU → 501–750 sq ft
- 24,000 BTU → 751–1,000 sq ft
- 36,000 BTU → 1,001–1,500 sq ft
Note: Insulation quality, ceiling height, sun exposure, and appliance heat load may affect sizing.
Does it heat as well as cool?
Yes. All 5th Gen models are full heat pumps, providing both heating and cooling for true year-round comfort in a single system.
Is it Wi-Fi compatible?
Yes. Control your system from anywhere using the MRCOOL SmartHVAC app (iOS & Android). It also works with Amazon Alexa and Google Assistant for convenient hands-free voice control.
What is the warranty?
Your purchase is backed by MRCOOL's industry-leading warranty:
- 7-Year Compressor Warranty — replacement coverage if the compressor fails within 7 years
- 5-Year Parts Warranty — full parts coverage for 5 years from date of purchase
Recommended BTU By Room Size
| BTU Capacity | Recommended Room Size (Sq. Ft.) |
|---|---|
| 9,000 BTU | 180 – 375 sq. ft. |
| 12,000 BTU | 351 – 500 sq. ft. |
| 18,000 BTU | 501 – 750 sq. ft. |
| 24,000 BTU | 751 – 1,000 sq. ft. |
| 36,000 BTU | 1,001 – 1,500 sq. ft. |
Note: Actual performance may vary depending on room insulation, ceiling height, number of windows, climate zone, and heat-generating appliances.
