The Della Optima Pro CloudAir 9,000 BTU 230V is the better DIY mini-split overall, rated 4.5 to 3.2. The Della Optima Pro CloudAir 9,000 BTU 230V leads on value and cold weather. The MrCool DIY 5th Gen 9,000 BTU 115V wins on efficiency and noise. The Della Optima Pro CloudAir 9,000 BTU 230V costs $1,280.04 less ($1,049.96 vs $2,330).
The best value for heating through a cold winter, if you can pull a vacuum yourself or pay someone to. It holds its full rated heat at 5 °F for far less than a quick-connect unit that does the same.
Amazon $1,049.96 Della $1,049.96For someone who wants a true plug-together install with no tools beyond a drill, and a warranty that survives it. Expect to pay well over the price of a flare unit with the same cold-weather output.
Amazon MRCOOL DIY Direct $2,330Prices were last checked October 21, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Each factor is scored 0-100 against the same fixed reference points for every 9,000 BTU DIY mini-split; a clear win is highlighted. How we rank explains each one.
| Factor weight | Della Optima Pro CloudAir 9,000 BTU 230V | MrCool DIY 5th Gen 9,000 BTU 115V |
|---|---|---|
| Overall rating | 4.5/5 | 3.2/5 |
| Value 35% | 94 $115 per 1,000 Btu/h of heat at 5 °F | 12 $319 per 1,000 Btu/h of heat at 5 °F |
| Cold weather 25% | 100 keeps 101% of its heat at 5 °F, heats down to -22 °F | 54 keeps 73% of its heat at 5 °F, heats down to -13 °F |
| Efficiency 20% | 70 10.5 HSPF2, 25 SEER2, COP 1.80 at 5 °F | 87 11.5 HSPF2, 23.6 SEER2, COP 2.16 at 5 °F |
| Warranty 15% | 70 lifetime parts once registered, no compressor term stated | 64 7-year compressor, 5-year parts |
| Noise 5% | 67 indoor unit from 26 dB(A) | 100 indoor unit from 18 dB(A) |
| Della Optima Pro CloudAir 9,000 BTU 230V | MrCool DIY 5th Gen 9,000 BTU 115V | |
|---|---|---|
| Capacity (certified) | ||
| Size (nominal) | 9,000 BTU | 9,000 BTU |
| Cooling at 95 °F | 9,000 Btu/h | 9,000 Btu/h |
| Heating at 47 °F | 9,000 Btu/h | 10,000 Btu/h |
| Heating at 17 °F (max) | 10,000 Btu/h | 7,800 Btu/h |
| Heating at 5 °F (max) | 9,100 Btu/h | 7,300 Btu/h |
| Heat kept at 5 °F | 101% | 73% |
| Price per 1,000 Btu/h at 5 °F | $115 | $319 |
| Efficiency (certified) | ||
| HSPF2 (Region IV) | 10.5 | 11.5 |
| SEER2 | 25 | 23.6 |
| EER2 | 14.5 | 14 |
| COP at 5 °F | 1.80 | 2.16 |
| ENERGY STAR | ENERGY STAR Cold Climate | ENERGY STAR Cold Climate |
| AHRI certificate | 218471006 | 216032543 |
| Operating range | ||
| Heats down to | -22 °F | -13 °F |
| Cooling range | 5 to 131 °F | -13 to 122 °F |
| Installation | ||
| Line set connection | Flare fittings (vacuum pump needed) | Quick-connect (no vacuum pump) |
| Line set | 16.4 ft included, up to 49 ft | 25 ft included, up to 75 ft |
| Voltage | 230 V | 115 V |
| Refrigerant | R-454B | R-454B |
| Indoor unit | 048-TPH-9K2V-C-IN | DIY-09-HP-WMAH-115D25-O |
| Outdoor unit | 048-TPH-9K2V-25S-OUT | DIY-09-HP-C-115D25-O |
| Build | ||
| Indoor noise | 26–42 dB(A) | 18–43 dB(A) |
| Outdoor noise | 55 dB(A) | 54 dB(A) |
| Wi-Fi | Built in | Built in |
| Room size (maker) | up to 400 sq ft | up to 400 sq ft |
| Weight | indoor 20.7 lb / outdoor 54 lb | indoor 24.9 lb / outdoor 65.5 lb |
| Warranty | lifetime parts (registered) | 7 yr compressor, 5 yr parts |
| Warranty with DIY install | Yes | Yes |
| Released | 2026-05 | - |
