A low price for a self-installer who owns or will rent a vacuum pump. The Klimaire DIY is the same certified system with quick-connect lines, and Della’s Optima has near-identical ratings for less.
Price checked October 21, 2026. As an Amazon Associate we earn from qualifying purchases.
The rating comes from 5 measured or published factors, each scored 0-100 against fixed reference points for its size. How we rank explains each one.
| Capacity (certified) | |
|---|---|
| Size (nominal) | 18,000 BTU |
| Cooling at 95 °F | 18,000 Btu/h |
| Heating at 47 °F | 19,000 Btu/h |
| Heating at 17 °F (max) | 17,500 Btu/h |
| Heating at 5 °F (max) | 13,600 Btu/h |
| Heat kept at 5 °F | 72% |
| Price per 1,000 Btu/h at 5 °F | $113 |
| Efficiency (certified) | |
| HSPF2 (Region IV) | 10 |
| SEER2 | 23 |
| EER2 | 12.5 |
| COP at 5 °F | 1.80 |
| ENERGY STAR | ENERGY STAR Cold Climate |
| AHRI certificate | 217048752 |
| Operating range | |
| Heats down to | -13 °F |
| Cooling range | 5 to 131 °F |
| Installation | |
| Line set connection | Flare fittings (vacuum pump needed) |
| Line set | 16 ft included, up to 65 ft |
| Voltage | 230 V |
| Refrigerant | R-454B |
| Indoor unit | WT018GLSI24HLG |
| Outdoor unit | YN018GLSI24RPG |
| Build | |
| Indoor noise | 34–50 dB(A) |
| Outdoor noise | 53 dB(A) |
| Wi-Fi | Built in |
| Room size (maker) | up to 750 sq ft |
| Weight | indoor 30.9 lb / outdoor 90.4 lb |
| Warranty | 10 yr compressor, 7 yr parts |
| Warranty with DIY install | Yes |
| DIY install warranty | 5 yr compressor, 5 yr parts |
| Released | 2025-06 |
The cheapest way into a certified, cold-capable heat pump, for a self-installer with a vacuum pump. Pioneer’s Quantum Ultra and the quick-connect Klimaire DIY have near-identical certified ratings.
Amazon $1,319.96 Della $1,499.96The 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 $1,679For 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 $2,910Compare the Pioneer Quantum Ultra 18,000 BTU 230V with any other DIY mini-split →
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