An 18,000 BTU unit heats and cools an open living area, a finished basement or a two-car garage. Every model here runs on 230 V. This is the size where cold-climate models pull furthest ahead, keeping nearly all of their rated heat at 5 °F where standard models lose a quarter or more.
Prices 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.
Full ranking 10
- Della Optima Pro CloudAir 18,000 BTU 230V#1 of 10Full review
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 $1,849.96$1,849.9617,80010Flare$104 - Pioneer Quantum Hyperformance 18,000 BTU 230V#2 of 10Full review
Full rated heat in deep cold at a fair price, for a self-installer comfortable with a vacuum pump. Della’s Optima Pro has near-identical certified ratings for a little less.
Amazon $1,878 Pioneer Mini Split store $1,878$1,87817,80010Flare$106 - Perfect Aire 4th Gen Quick Connect 18,000 BTU 230V#3 of 10Full review
A quick-connect unit with one of the longest warranties for a self-install, priced below MrCool’s DIY 5th Gen. Its −4 °F heating limit rules it out as the only heat in a very cold climate.
Amazon $1,981.82$1,981.8218,00010Quick-connect$110 - MrCool DIY Hyper Heat 5th Gen 18,000 BTU 230V#4 of 10Full review
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 $3,205$3,17318,00011Quick-connect$176 - Della Optima CloudAir 18,000 BTU 230V#5 of 10Full review
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 $1,499.96$1,319.9613,60010Flare$97 - Klimaire KIWQ-KOIQ DIY 5th Gen 18,000 BTU 230V#6 of 10Full review
The 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 $1,679$1,67913,60010Quick-connect$123 - Pioneer Quantum Ultra 18,000 BTU 230V#7 of 10Full review
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.
Pioneer Mini Split store $1,538$1,53813,60010Flare$113 - MrCool DIY 5th Gen 18,000 BTU 230V#8 of 10Full review
For 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 $2,910$2,91012,80011.5Quick-connect$227 - MrCool DIY Easy Pro 18,000 BTU 230V#9 of 10Full review
A middle step between MrCool’s Select and DIY 5th Gen: quick-connect and a fair warranty, but it loses much of its heat in a cold snap. Best for mild winters.
MRCOOL DIY Direct $1,806$1,8069,8008.5Quick-connect$184 - MrCool DIY Select 18,000 BTU 230V#10 of 10Full review
For 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 $1,690$1,6909,5008.5Quick-connect$178
