The smallest mini splits available are 6,000 BTU units, capable of cooling rooms as small as 150 sq ft. The most common small size is 9,000 BTU, which handles 250–350 sq ft — perfect for bedrooms, home offices, server closets, and small additions. Mitsubishi's MSZ-FH09 (9K) is the best overall small mini split: 33.1 SEER2, 19 dB noise, and cold-climate heating to -13°F. For budget buyers, the MrCool DIY 12K is the smallest model in their lineup at a much lower price point.
Smallest Mini Split Models Available
| Brand | Model | BTU | SEER2 | Noise (Low) | Price | Notes |
|---|---|---|---|---|---|---|
| Mitsubishi | MSZ-FH09 | 9,000 | 33.1 | 19 dB | $1,600–$2,000 | Best overall small unit |
| Daikin | Aurora 09 | 9,000 | 25.5 | 19 dB | $1,300–$1,700 | Best warranty |
| Fujitsu | RLS3H 09 | 9,000 | 33.0 | 19 dB | $1,200–$1,600 | Best value premium |
| LG | Art Cool 09 | 9,000 | 27.5 | 20 dB | $1,100–$1,400 | Best smart features |
| Mitsubishi | MSZ-GL06 | 6,000 | 24.0 | 22 dB | $1,200–$1,600 | Smallest available |
| Senville | SENL-09CD | 9,000 | 19.0 | 28 dB | $500–$750 | Cheapest small unit |
When You Need a Small Mini Split
Small mini splits (6K–9K BTU) are ideal for single bedrooms (150–300 sq ft), home offices (100–250 sq ft), server rooms and equipment closets (cooling heat-generating equipment), sunrooms and enclosed porches (150–250 sq ft), studio apartments (300–400 sq ft with low heat gain), and workshop areas within a larger garage.
Sizing for Small Rooms
| Room | Size | Insulation | Sun Exposure | Recommended BTU |
|---|---|---|---|---|
| Small bedroom | 150 sq ft | Good | Shaded | 6,000 |
| Standard bedroom | 250 sq ft | Average | Moderate | 9,000 |
| Home office | 150 sq ft | Good | Moderate | 6,000–9,000 |
| Server closet | 100 sq ft | N/A | N/A | 9,000 (heat load from equipment) |
| Small sunroom | 200 sq ft | Poor (glass) | Heavy | 9,000–12,000 |
Key Takeaways
- The smallest mini split air conditioners for small rooms, offices, and server closets
- 6K and 9K BTU models compared by size, noise, and efficiency
- 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