The Della Optima Pro CloudAir 18,000 BTU 230V is the better DIY mini-split overall, rated 4.3 to 2.4. The Della Optima Pro CloudAir 18,000 BTU 230V leads on value and efficiency. The MrCool DIY Select 18,000 BTU 230V wins on noise. The MrCool DIY Select 18,000 BTU 230V costs $159.96 less ($1,690 vs $1,849.96).
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 $1,849.96 Della $1,849.96For mild climates and occasional use, where a low price for a quick-connect unit matters most. The short warranty and weak cold-weather output make it a poor main heat source.
Amazon $1,690 MRCOOL DIY Direct $1,690Prices 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 18,000 BTU DIY mini-split; a clear win is highlighted. How we rank explains each one.
| Factor weight | Della Optima Pro CloudAir 18,000 BTU 230V | MrCool DIY Select 18,000 BTU 230V |
|---|---|---|
| Overall rating | 4.3/5 | 2.4/5 |
| Value 35% | 90 $104 per 1,000 Btu/h of heat at 5 °F | 51 $178 per 1,000 Btu/h of heat at 5 °F |
| Cold weather 25% | 99 keeps 99% of its heat at 5 °F, heats down to -22 °F | 6 keeps 53% of its heat at 5 °F |
| Efficiency 20% | 57 10 HSPF2, 23.5 SEER2, COP 1.80 at 5 °F | 11 8.5 HSPF2, 17.3 SEER2, COP 1.75 at 5 °F |
| Warranty 15% | 70 lifetime parts once registered, no compressor term stated | 0 2-year compressor, 1-year parts |
| Noise 5% | 29 indoor unit from 34 dB(A) | 100 indoor unit from 18.5 dB(A) |
| Della Optima Pro CloudAir 18,000 BTU 230V | MrCool DIY Select 18,000 BTU 230V | |
|---|---|---|
| Capacity (certified) | ||
| Size (nominal) | 18,000 BTU | 18,000 BTU |
| Cooling at 95 °F | 18,000 Btu/h | 17,000 Btu/h |
| Heating at 47 °F | 18,000 Btu/h | 18,000 Btu/h |
| Heating at 17 °F (max) | 15,500 Btu/h | 18,700 Btu/h |
| Heating at 5 °F (max) | 17,800 Btu/h | 9,500 Btu/h |
| Heat kept at 5 °F | 99% | 53% |
| Price per 1,000 Btu/h at 5 °F | $104 | $178 |
| Efficiency (certified) | ||
| HSPF2 (Region IV) | 10 | 8.5 |
| SEER2 | 23.5 | 17.3 |
| EER2 | 12.5 | 9 |
| COP at 5 °F | 1.80 | 1.75 |
| ENERGY STAR | ENERGY STAR Cold Climate | Not ENERGY STAR |
| AHRI certificate | 218471004 | 218004486 |
| Operating range | ||
| Heats down to | -22 °F | - |
| Cooling range | 5 to 131 °F | - |
| Installation | ||
| Line set connection | Flare fittings (vacuum pump needed) | Quick-connect (no vacuum pump) |
| Line set | 16.4 ft included, up to 65 ft | 11.5 ft included, up to 75 ft |
| Voltage | 230 V | 230 V |
| Refrigerant | R-454B | R-454B |
| Indoor unit | 048-TPH-18K2V-C-IN | DIYS-18-HP-WMAH-230A13-O |
| Outdoor unit | 048-TPH-18K2V-23S-OUT | DIYS-18-HP-C-230A11-O |
| Build | ||
| Indoor noise | 34–48 dB(A) | 18.5–46.5 dB(A) |
| Outdoor noise | 58 dB(A) | 55 dB(A) |
| Wi-Fi | Built in | Built in |
| Room size (maker) | up to 1,000 sq ft | up to 800 sq ft |
| Weight | indoor 30.9 lb / outdoor 93.7 lb | indoor 30.6 lb / outdoor 62.6 lb |
| Warranty | lifetime parts (registered) | 2 yr compressor, 1 yr parts |
| Warranty with DIY install | Yes | Yes |
| Released | 2026-05 | - |
