A 9,000 BTU unit suits a bedroom, home office or small addition up to about 400 square feet in a mild climate, less in a cold one or under a poorly insulated roof. Most come in 115 V versions that run on an ordinary dedicated circuit, and they are the cheapest units to buy, though always the most expensive per Btu.
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 11
- Della Optima Pro CloudAir 9,000 BTU 230V#1 of 11Full 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 $1,049.96 Della $1,049.96$1,049.969,10010.5Flare$115 - Pioneer Quantum Hyperformance 9,000 BTU 230V#2 of 11Full 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 $1,311 Pioneer Mini Split store $1,318$1,3119,50010.5Flare$138 - Della Optima CloudAir 9,000 BTU 230V#3 of 11Full 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 $879.96 Della $879.96$879.967,1009.5Flare$124 - Della Optima CloudAir 9,000 BTU 115V#4 of 11Full 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 $899.96 Della $899.96$899.967,1009.5Flare$127 - Klimaire KIWQ-KOIQ DIY 5th Gen 9,000 BTU 115V#5 of 11Full 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 $1,099$1,0997,5009.5Quick-connect$147 - Pioneer Quantum Ultra 9,000 BTU 115V#6 of 11Full 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.
Amazon $1,088 Pioneer Mini Split store $1,088$1,0887,5009.5Flare$145 - Pioneer Quantum Ultra 9,000 BTU 230V#7 of 11Full 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.
Amazon $1,058 Pioneer Mini Split store $1,058$1,0587,1009.5Flare$149 - Perfect Aire 4th Gen Quick Connect 9,000 BTU 115V#8 of 11Full 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.
AmazonNo price9,2009.5Quick-connect- - MrCool DIY 5th Gen 9,000 BTU 115V#9 of 11Full 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 $2,330$2,3307,30011.5Quick-connect$319 - MrCool DIY Easy Pro 9,000 BTU 115V#10 of 11Full 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 $1,487$1,4876,2009.2Quick-connect$240 - MrCool DIY Select 9,000 BTU 115V#11 of 11Full 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 $1,249 MRCOOL DIY Direct $1,249$1,2496,0008.8Quick-connect$208
