What's in the box
- 1 × MRCOOL® DIY® 5th Gen 18K BTU Multi-Zone Condenser
- 3 × MRCOOL® DIY® 5th Gen 9K BTU Wall-Mounted Air Handlers
- 3 × Wireless Remote Controls
- 3 × 25 ft R-454B Quick Connect® Line Sets
- 3 × DIYPRO® Cables
- Installation Documentation
DIY-friendly installation.
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Designed for simplified installation using MRCOOL® Quick Connect® technology.
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Electrical requirements, permits, and building codes may vary by location.
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Professional electrical work may be required depending on local regulations, system placement, and installation conditions.
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Always review the product installation manual before purchase and installation.
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Base Parts Warranty: 5 Years
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Base Compressor Warranty: 7 Years
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Eligible for the MRCOOL® Care Program
Warranty terms may require registration and must follow MRCOOL® warranty conditions. Please refer to the product warranty documentation for full warranty terms, registration requirements, and coverage details.
- Free U.S. curbside delivery within the Lower 48 States on qualifying orders
- Orders ship from U.S. warehouse locations
- Delivery times may vary by destination, product availability, and carrier scheduling
- Returns are accepted within 30 days for unused, uninstalled products that meet return eligibility requirements
- Approved returns may be subject to a restocking fee
Manuals & documents
MODEL: CHD-DIY5GEN-MZ18-090909-25-25-25
Three-Room Comfort Made Simple.
Need heating and cooling for three separate smaller rooms without installing three separate outdoor systems?
The MRCOOL® DIY® 5th Gen 18K BTU 3-Zone Mini Split System is designed for flexible comfort across three smaller spaces, such as bedrooms, home offices, guest rooms, studios, or small apartments.
This bundle pairs one 18K BTU DIY® 5th Gen multi-zone condenser with three 9K BTU wall-mounted air handlers, giving each room its own indoor unit, remote control, and temperature setting.
Each 9K air handler is suitable for smaller rooms, while the 18K condenser supports up to three compatible indoor zones and a combined comfort area of up to around 750 sq ft.
With MRCOOL® Quick Connect® technology, R-454B refrigerant, DC inverter performance, smart app control, and voice control compatibility, this system gives homeowners an easier path to efficient three-room heating and cooling.
Smart. Efficient. Flexible. Built for three-zone comfort.
Why You’ll Love It
✅ Complete 3-zone mini split system
✅ Includes three 9K BTU wall-mounted air handlers
✅ One outdoor condenser powers all three indoor zones
✅ Independent room-by-room comfort control
✅ Ideal for bedrooms, offices, guest rooms, or smaller living spaces
✅ High-efficiency 23.9 SEER2 performance
✅ R-454B refrigerant
✅ DC inverter technology
✅ SmartHVAC® app compatibility
✅ Works with Amazon Alexa and Google Assistant
✅ Follow Me® comfort sensing
✅ Quiet Mode and Auto Cool
✅ Reusable filters
✅ DIY-friendly Quick Connect® technology
✅ 7-Year Compressor / 5-Year Parts Base Warranty
Best For
Three Bedrooms • Bedrooms + Home Office • Guest Rooms • Small Apartments • Studios • Three Small Living Areas • Multi-Room Comfort • DIY Mini-Split Installations
Important Sizing Note
This bundle is sold as a 3-zone system and includes three indoor air handlers.
The outdoor condenser is rated at 18K BTU total system capacity and supports up to three compatible indoor zones. This setup is best for three smaller rooms with a combined comfort area of up to around 750 sq ft, not three large rooms all requiring full output at the same time.
Zone Size Guide
| Zone | Air Handler Size | Recommended Room Size |
|---|---|---|
| Zone 1 | 9K BTU | 250–400 sq ft |
| Zone 2 | 9K BTU | 250–400 sq ft |
| Zone 3 | 9K BTU | 250–400 sq ft |
| Combined System | 18K BTU | Up to around 750 sq ft combined |
Room size recommendations may vary depending on insulation quality, ceiling height, climate, window exposure, sun exposure, and room layout.
Need a Different 3-Zone Setup?
This 9K + 9K + 9K bundle is best for three smaller rooms.
For larger rooms, mixed room sizes, open layouts, or higher heating and cooling demand, consider stepping up to a larger MRCOOL® DIY multi-zone system.
Explore:
9K + 9K + 12K Multi-Zone Systems
9K + 12K + 12K Multi-Zone Systems
12K + 12K + 12K Multi-Zone Systems
3-Zone Mini-Split Systems
Multi-Zone Mini-Split Systems
| Coverage Area | Up to 750 sq ft combined |
| Cooling Capacity | 18,000 BTU |
| Heating Capacity | 18,000 BTU |
| Voltage | 230V |
| Zone Type | 3 Zone |
| SEER2 | 23.9 |
| EER2 | 13 |
| HSPF2-4 | 10 |
| HSPF2-5 | 7.8 |
| Zone Setup | 9K + 9K + 9K |
| Air Handlers | 3 × 9K Wall-Mounted |
| Condenser Zones | Supports 3 zones |
| Included Zones | 3 zones included |
| Outdoor Model | DIY-MULTI3-18HP230D-O |
| Indoor Model | DIY-09-HP-WMAH-230D25-O |
| Outdoor Sound | 60 dB(A) |
| WiFi Control | Yes |
| App Control | SmartHVAC® App |
| Voice Control | Alexa / Google |
| Inverter Tech | DC Inverter |
| Refrigerant | R-454B |
| Refrigerant Volume | 61.73 oz |
| Line Sets | 3 × 25 ft included |
| Max Line Set | 172.2 ft total |
| Line Sizes | 1/4" Liquid / 3/8" Suction |
| Compressor Type | Rotary |
| Remote Controls | 3 |
| DIYPRO® Cables | 3 |
| Max Fuse | 20A |
| MCA | 16A |
| Phase / Cycle | 1 Phase / 60Hz |
| Certifications | AHRI, UL, ETL, Energy Star® |
| Base Warranty | 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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