The MrCool DIY Hyper Heat 5th Gen 18,000 BTU 230V is the better DIY mini-split overall, rated 4.0 to 3.4. The MrCool DIY Hyper Heat 5th Gen 18,000 BTU 230V leads on cold weather and value. The MrCool DIY 5th Gen 18,000 BTU 230V wins on efficiency. The MrCool DIY 5th Gen 18,000 BTU 230V costs $263 less ($2,910 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 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 $2,910Prices 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 5th Gen 18,000 BTU 230V |
|---|---|---|
| Overall rating | 4.0/5 | 3.4/5 |
| Value 35% | 52 $176 per 1,000 Btu/h of heat at 5 °F | 25 $227 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 | 52 keeps 71% of its heat at 5 °F, heats down to -13 °F |
| Efficiency 20% | 73 11 HSPF2, 21.2 SEER2, COP 1.99 at 5 °F | 92 11.5 HSPF2, 22.5 SEER2, COP 2.44 at 5 °F |
| Warranty 15% | 64 7-year compressor, 5-year parts | 64 7-year compressor, 5-year parts |
| Noise 5% | 93 indoor unit from 20.5 dB(A) | 100 indoor unit from 19 dB(A) |
| MrCool DIY Hyper Heat 5th Gen 18,000 BTU 230V | MrCool 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 | 18,000 Btu/h |
| Heating at 17 °F (max) | 20,300 Btu/h | 20,300 Btu/h |
| Heating at 5 °F (max) | 18,000 Btu/h | 12,800 Btu/h |
| Heat kept at 5 °F | 100% | 71% |
| Price per 1,000 Btu/h at 5 °F | $176 | $227 |
| Efficiency (certified) | ||
| HSPF2 (Region IV) | 11 | 11.5 |
| SEER2 | 21.2 | 22.5 |
| EER2 | 12.5 | 13.7 |
| COP at 5 °F | 1.99 | 2.44 |
| ENERGY STAR | ENERGY STAR Cold Climate | ENERGY STAR Cold Climate |
| AHRI certificate | 216032551 | 216032545 |
| Operating range | ||
| Heats down to | -22 °F | -13 °F |
| Cooling range | -22 to 122 °F | -13 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 | 25 ft included, up to 75 ft |
| Voltage | 230 V | 230 V |
| Refrigerant | R-454B | R-454B |
| Indoor unit | DIY-18-HP-WMAH-230D25-O | DIY-18-HP-WMAH-230D25-O |
| Outdoor unit | DIYHH-18-HP-C-230D25-O | DIY-18-HP-C-230D25-O |
| Build | ||
| Indoor noise | 20.5–54.5 dB(A) | 19–54.5 dB(A) |
| Outdoor noise | 58 dB(A) | 58.5 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 35.5 lb / outdoor 93.5 lb |
| Warranty | 7 yr compressor, 5 yr parts | 7 yr compressor, 5 yr parts |
| Warranty with DIY install | Yes | Yes |
