A 4-zone mini split system connects one outdoor unit to 4 indoor air handlers, each in a separate room with independent temperature control. The best 4-zone system in 2026 is the Mitsubishi MXZ-4C36NAHZ with MSZ-FH indoor units — delivering 29 SEER2 system efficiency, 19 dB indoor noise, and Hyper-Heat cold-climate capability. Budget buyers should consider the MrCool DIY 4-zone at $$3,800–$5,500 for genuine homeowner installation.
Best 4-Zone Mini Split Systems
| Rank | Brand/System | SEER2 | Indoor Noise | Cold-Climate | Warranty | System Price |
|---|---|---|---|---|---|---|
| 1 | Mitsubishi MXZ + MSZ-FH | 26 | 19 dB | -13°F (H2i) | 7–12 yr | $$10,000–$15,000 |
| 2 | Daikin MXL + Aurora | 24 | 19 dB | -13°F | 12 yr | $$8,500–$13,000 |
| 3 | Fujitsu AOU + RLS3H | 24 | 19 dB | -15°F | 10 yr | $$8,000–$12,000 |
| 4 | LG Multi F | 22 | 20 dB | -13°F | 10 yr | $$7,500–$11,000 |
| 5 | MrCool DIY Multi-Zone | 21 | 25 dB | -4°F | 7 yr | $$3,800–$5,500 |
Sizing Your 4-Zone System
The outdoor unit must be sized for the combined capacity of all indoor zones. Here are common 4-zone configurations:
| Configuration | Indoor Units | Outdoor Unit | Total BTU | Home Size |
|---|---|---|---|---|
| 12K + 12K + 12K + 12K | 4 × 12K wall-mount | 48K | 48,000 | 1400–2000 sq ft |
| 9K + 9K + 9K + 9K | 4 × 9K wall-mount | 36K | 36,000 | 1000–1400 sq ft |
| Mixed (large + small) | Mix of 9K–18K | 48K | Varies | Varies |
Worked Example: 4-Zone for a 4-Bedroom Colonial
Home: 1600 sq ft, 4 rooms needing independent climate control. Moderate climate (Charlotte, NC).
| Zone | Room | Size | BTU Needed | Indoor Unit |
|---|---|---|---|---|
| Zone 1 | Living Room | 450 sq ft | 15,000 | 15K wall-mount |
| Zone 2 | Master Bedroom | 300 sq ft | 9,000 | 9K wall-mount |
| Zone 3 | Bedroom 2 | 250 sq ft | 9,000 | 9K wall-mount |
| Zone 4 | Home Office | 200 sq ft | 9,000 | 9K wall-mount |
Total system capacity needed: 42,000 BTU Recommended outdoor unit: 42K+ outdoor compressor Estimated installed cost (Fujitsu): $11,200–$14,000 After $2,000 federal tax credit: $9,200–$12,000
Installation Cost Breakdown
| Component | Cost Range |
|---|---|
| Outdoor unit (equipment) | $3,200–$4,800 |
| 4 indoor units (equipment) | $3,600–$6,000 |
| Labor (4 zones) | $4,800–$7,200 |
| Electrical (circuit + disconnect) | $400–$800 |
| Materials (line sets, covers) | $800–$1,400 |
| Permit | $100–$200 |
| Total installed | $10,500–$16,500 |
| Federal tax credit (25C) | -$2,000 |
| Net cost | $8,500–$14,500 |
Multi-zone cost efficiency: A 4-zone system costs 30–40% less per zone than installing 4 separate single-zone systems because the outdoor unit, electrical work, and setup are shared. The trade-off: if the single outdoor unit fails, all 4 zones lose heating and cooling simultaneously.
Key Takeaways
- Top 4-zone mini split systems compared by specs, efficiency, and price
- Sizing guide for 4-room configurations with installation cost breakdowns
- Always verify specifications against the AHRI directory for independently certified performance data
- Consider the federal $2,000 tax credit and state rebates when calculating total cost