What's in the box
- MRCOOL® 18K DIY® 5th Gen 3-Zone Mini-Split Condenser
- DIYPro™ Communication Cable
- Wireless Remote Control
- Installation Accessories
- MRCOOL® Warranty
MODEL: DIY-MULTI3-18HP230D-O
DIY Multi-Zone Climate Control for Up to 3 Rooms (750 sq. ft.)
Take total control of your home’s comfort with the MRCOOL® 18K DIY® 5th Generation Multi-Zone Mini-Split Condenser — a high-performance, energy-efficient system designed for reliable heating and cooling across up to three separate rooms. Perfect for homes, apartments, basements, garages, or offices totaling up to 750 sq. ft.
Delivering a top-tier SEER2 rating of 23.9 and HSPF2-4 of 10, this 1.5-ton condenser offers outstanding efficiency and year-round savings. The game-changing Quick Connect® pre-charged line sets — now filled with eco-conscious R-454B refrigerant — allow for fast, clean, and fully DIY-friendly installation with no vacuuming, gauges, or professional assistance required.
Pair it with up to 3 MRCOOL® 5th Gen DIY® Air Handlers to personalize each room’s climate to your exact preference. Integrated Wi-Fi control via the SmartHVAC® app, Amazon Alexa, and Google Assistant lets you manage schedules, modes, and temperature settings remotely — or by voice command.
Engineered with durable, weather-resistant components and a quiet, efficient rotary inverter compressor, this unit ensures long-lasting, whisper-quiet operation at just 60 dBA. It’s backed by an exceptional Limited Lifetime Compressor Replacement Warranty (with registration), giving you total confidence in your investment.
Why You’ll Love It
✅ Controls Up to 3 Zones — Connects to three air handlers for flexible, multi-room heating and cooling.
✅ Seamless DIY Installation — Use MRCOOL® Quick Connect® pre-charged line sets for a no-vacuum, tool-free setup.
✅ Top Energy Efficiency — SEER2 23.9 and HSPF2-4 10 for lower energy bills and eco-friendly performance.
✅ Smart-Home Compatible — Control your system via the SmartHVAC® app, Alexa, and Google Assistant.
✅ Follow Me® Technology — Tracks temperature where you are, not just where the unit is.
✅ Ultra-Quiet, Reliable Operation — Rotary inverter compressor for low-noise, efficient comfort (60 dBA).
✅ Built-In Future-Ready Design — Features durable components and eco-conscious R-454B refrigerant.
✅ Industry-Leading Warranty — Limited Lifetime Compressor (with registration), 7-Year Compressor, and 5-Year Parts Warranty.
What You Need for a Complete System
For full operation and optimal performance, pair this condenser with:
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MRCOOL® DIY® 5th Gen Multi-Zone Air Handlers (up to 3 total)
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MRCOOL® Quick Connect® Pre-Charged Line Sets (available in multiple lengths — sold separately)
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DIYPro™ Communication Cables (25ft included with each air handler)
Optional Accessories:
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MRCOOL® Wall Mount Bracket
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Additional Quick Connect® Line Sets
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Coupler Kits (for line set extensions)
| Attribute | Details |
|---|---|
| BTU Capacity | 18,000 BTU |
| Voltage | 208/230V |
| Zones Supported | Up to 3 |
| SEER2 | 23.9 |
| HSPF2-4 / HSPF2-5 | 10 / 7.8 |
| Refrigerant Type | R-454B |
| Line Set Compatibility | MRCOOL® Quick Connect® |
| Max Line Set Length (ft) | 172.2 |
| Liquid Line Size | 1/4″ |
| Suction Line Size | 3/8″ |
| Sound Rating (dBA) | 60 |
| Wi-Fi Compatibility | Yes (SmartHVAC App, Alexa, Google Assistant) |
| Warranty | Limited Lifetime Compressor (registered), 7-Year Compressor, 5-Year Parts |
Questions, answered
Everything homeowners ask before buying a MRCOOL® system.
Installation
Do I need an HVAC technician to install this?
No. MRCOOL® DIY systems are designed for homeowner installation. The pre-charged Quick Connect® line set means there's no refrigerant handling, no vacuum pump, and no special tools or license required.
How long does installation take?
Most single-zone systems go in within a few hours: mount the indoor air handler, set the outdoor condenser, connect the pre-charged line set, and power it on.
Do I need an electrician?
The system needs a dedicated circuit. Most homeowners have a licensed electrician add the breaker and disconnect — everything else you can do yourself.
Sizing & compatibility
What BTU size do I need?
As a rule of thumb: up to 400 sq ft → 9–12K BTU, 400–600 sq ft → 12–18K, 600–1,000 sq ft → 18–24K. Use the room-size guide above and factor in insulation, ceiling height and sun exposure.
Will it heat in winter?
Yes — these are heat pumps, so they heat and cool. Many MRCOOL® systems keep heating in sub-freezing temperatures; check each model's spec sheet for its low-temperature heating range.
115V or 230V — which do I need?
9K–12K units are usually 115V (standard outlet circuit); 18K and larger are typically 230V. The voltage is shown in the product options and specifications.
Warranty & support
What warranty is included?
MRCOOL® systems carry manufacturer warranty coverage — typically 5–10 years on major components when you register your system after installation.
How do I get help choosing or installing?
Email support@coolheatdirect.com — our U.S. team replies within one business day with sizing, voltage and compatibility help.
Shipping & returns
How fast does it ship?
Most products ship in 3–5 business days with free curbside delivery in the continental U.S. The freight carrier calls to schedule your delivery.
Can I return it?
Returns are accepted within 30 days on new, unopened items in original packaging. A restocking fee may apply to HVAC equipment — we always confirm before issuing a return authorization.
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