MRCOOL DIY 5th Gen 3-Zone Mini-Split System | Climate Control for Three Rooms, No Technician Required
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🛡 Warranty: Manufacturer warranty included. Coverage varies by product — see product description below for full warranty details.
Best for: Multi-room cabins, additions, and small homes where three independent zones make sense.
Why people buy it: Zoned comfort without ductwork and without opening refrigerant lines.
Watch out for: Three-zone systems require real planning. If you are not comfortable sizing rooms and routing multiple line sets, get help before buying.
Three rooms, three different temperatures, one outdoor unit, one installation project. The MRCOOL DIY 5th Gen 3-zone system is built for off-grid homes and homesteads where different spaces have different needs: a cooler bedroom, a warmer main living area, a workshop that only runs when you're out there. Each air handler operates independently. Each uses the same pre-charged quick-connect line set that makes MRCOOL the go-to DIY mini-split for people who want to do this themselves without compromising on system quality.
MRCOOL DIY 3-Zone System Key Features
- Three independent zones — each air handler runs independently with its own temperature setting; no zone affects another
- True DIY installation — pre-charged R-454B quick-connect line sets for all three zones; no vacuum pump, no refrigerant license
- Heats down to -13°F — cold-climate heat pump across all zones simultaneously
- Single 230V outdoor condenser — one outdoor unit for all three zones; less exterior equipment, less installation work
- WiFi and per-zone app control — MRCOOL Smart HVAC app; control and schedule each zone from your phone
- Gold Fin condenser coil — corrosion-resistant outdoor unit for all climate conditions
- Strong upsell path to 4-zone — if you need a fourth room later, MRCOOL's multi-zone platform scales
Specifications
| Zone Count | 3 zones |
| Total System Capacity | Up to 18,000 BTU (condenser) |
| Coverage Area | Up to 750 sq ft total (distributed across zones) |
| Voltage | 208-230V, 60Hz, 1PH |
| Refrigerant | R-454B (pre-charged line sets) |
| Condenser Model | DIY-MULTI3-18HP230D-O |
| Min Operating Temp (Heating) | -13°F |
| Available Air Handler Sizes | 9K, 12K BTU per zone |
| Certifications | UL, ETL, AHRI |
| Warranty | 5 years parts / 7 years compressor |
What's Included
- 1x 18,000 BTU outdoor multi-zone condenser (DIY-MULTI3-18HP230D-O)
- 3x indoor wall-mount air handlers (BTU sizes per selected configuration)
- 3x pre-charged quick-connect line sets (25 ft each)
- Smart HVAC Controller Modules (WiFi) for each zone
- Remote controls for each zone
- Installation hardware