The Della Optima Pro CloudAir 18,000 BTU 230V is the better DIY mini-split overall, rated 4.3 to 3.7. The Della Optima Pro CloudAir 18,000 BTU 230V leads on cold weather and value. The Klimaire KIWQ-KOIQ DIY 5th Gen 18,000 BTU 230V costs $170.96 less ($1,679 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 $1,849.96The best-value quick-connect line: the same certified system as Pioneer’s Quantum Ultra, close to Della’s Optima, without the vacuum pump, for the same price or a few hundred dollars more.
Amazon $1,679Prices 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 | Klimaire KIWQ-KOIQ DIY 5th Gen 18,000 BTU 230V |
|---|---|---|
| Overall rating | 4.3/5 | 3.7/5 |
| Value 35% | 90 $104 per 1,000 Btu/h of heat at 5 °F | 80 $123 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 | 53 keeps 72% of its heat at 5 °F, heats down to -13 °F |
| Efficiency 20% | 57 10 HSPF2, 23.5 SEER2, COP 1.80 at 5 °F | 56 10 HSPF2, 23 SEER2, COP 1.80 at 5 °F |
| Warranty 15% | 70 lifetime parts once registered, no compressor term stated | 64 7-year compressor, 5-year parts |
| Noise 5% | 29 indoor unit from 34 dB(A) | 29 indoor unit from 34 dB(A) |
| Della Optima Pro CloudAir 18,000 BTU 230V | Klimaire KIWQ-KOIQ DIY 5th Gen 18,000 BTU 230V | |
|---|---|---|
| Capacity (certified) | ||
| Size (nominal) | 18,000 BTU | 18,000 BTU |
| Cooling at 95 °F | 18,000 Btu/h | 18,000 Btu/h |
| Heating at 47 °F | 18,000 Btu/h | 19,000 Btu/h |
| Heating at 17 °F (max) | 15,500 Btu/h | 17,500 Btu/h |
| Heating at 5 °F (max) | 17,800 Btu/h | 13,600 Btu/h |
| Heat kept at 5 °F | 99% | 72% |
| Price per 1,000 Btu/h at 5 °F | $104 | $123 |
| Efficiency (certified) | ||
| HSPF2 (Region IV) | 10 | 10 |
| SEER2 | 23.5 | 23 |
| EER2 | 12.5 | 12.5 |
| COP at 5 °F | 1.80 | 1.80 |
| ENERGY STAR | ENERGY STAR Cold Climate | ENERGY STAR Cold Climate |
| AHRI certificate | 218471004 | 218067070 |
| Operating range | ||
| Heats down to | -22 °F | -13 °F |
| Cooling range | 5 to 131 °F | 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 | 25 ft included, up to 65 ft |
| Voltage | 230 V | 230 V |
| Refrigerant | R-454B | R-454B |
| Indoor unit | 048-TPH-18K2V-C-IN | KIWQ18H2-45T |
| Outdoor unit | 048-TPH-18K2V-23S-OUT | KOIQ18H2-45T |
| Build | ||
| Indoor noise | 34–48 dB(A) | 34–50 dB(A) |
| Outdoor noise | 58 dB(A) | 53 dB(A) |
| Wi-Fi | Built in | Built in |
| Room size (maker) | up to 1,000 sq ft | - |
| Weight | indoor 30.9 lb / outdoor 93.7 lb | indoor 30.9 lb / outdoor 90.4 lb |
| Warranty | lifetime parts (registered) | 7 yr compressor, 5 yr parts |
| Warranty with DIY install | Yes | Yes |
| Released | 2026-05 | 2025-10 |
