The MrCool DIY Hyper Heat 5th Gen 18,000 BTU 230V is the better DIY mini-split overall, rated 4.0 to 2.4. The MrCool DIY Hyper Heat 5th Gen 18,000 BTU 230V leads on efficiency and warranty. The MrCool DIY Select 18,000 BTU 230V costs $1,483 less ($1,690 vs $3,173).
For cold-climate homes where a quick-connect install matters more than price: it holds its full heat far colder than other quick-connect units. Flare-connect units match its cold-weather output for much less.
Amazon $3,173 MRCOOL DIY Direct $3,205For 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 | MrCool DIY Hyper Heat 5th Gen 18,000 BTU 230V | MrCool DIY Select 18,000 BTU 230V |
|---|---|---|
| Overall rating | 4.0/5 | 2.4/5 |
| Value 35% | 52 $176 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% | 100 keeps 100% of its heat at 5 °F, heats down to -22 °F | 6 keeps 53% of its heat at 5 °F |
| Efficiency 20% | 73 11 HSPF2, 21.2 SEER2, COP 1.99 at 5 °F | 11 8.5 HSPF2, 17.3 SEER2, COP 1.75 at 5 °F |
| Warranty 15% | 64 7-year compressor, 5-year parts | 0 2-year compressor, 1-year parts |
| Noise 5% | 93 indoor unit from 20.5 dB(A) | 100 indoor unit from 18.5 dB(A) |
| MrCool DIY Hyper Heat 5th Gen 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) | 20,300 Btu/h | 18,700 Btu/h |
| Heating at 5 °F (max) | 18,000 Btu/h | 9,500 Btu/h |
| Heat kept at 5 °F | 100% | 53% |
| Price per 1,000 Btu/h at 5 °F | $176 | $178 |
| Efficiency (certified) | ||
| HSPF2 (Region IV) | 11 | 8.5 |
| SEER2 | 21.2 | 17.3 |
| EER2 | 12.5 | 9 |
| COP at 5 °F | 1.99 | 1.75 |
| ENERGY STAR | ENERGY STAR Cold Climate | Not ENERGY STAR |
| AHRI certificate | 216032551 | 218004486 |
| Operating range | ||
| Heats down to | -22 °F | - |
| Cooling range | -22 to 122 °F | - |
| Installation | ||
| Line set connection | Quick-connect (no vacuum pump) | Quick-connect (no vacuum pump) |
| Line set | 25 ft included, up to 75 ft | 11.5 ft included, up to 75 ft |
| Voltage | 230 V | 230 V |
| Refrigerant | R-454B | R-454B |
| Indoor unit | DIY-18-HP-WMAH-230D25-O | DIYS-18-HP-WMAH-230A13-O |
| Outdoor unit | DIYHH-18-HP-C-230D25-O | DIYS-18-HP-C-230A11-O |
| Build | ||
| Indoor noise | 20.5–54.5 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 800 sq ft | up to 800 sq ft |
| Weight | indoor 35.5 lb / outdoor 99.9 lb | indoor 30.6 lb / outdoor 62.6 lb |
| Warranty | 7 yr compressor, 5 yr parts | 2 yr compressor, 1 yr parts |
| Warranty with DIY install | Yes | Yes |
