36,000 BTU is the largest single-zone DIY size, for big open spaces such as a barn, a shop or a great room. Few makers sell one, and those that do lose more of their heat in the cold than their smaller units.
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 2
- Klimaire KIWQ-KOIQ DIY 5th Gen 36,000 BTU 230V#1 of 2Full 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 $2,619$2,61920,4009Quick-connect$128 - MrCool DIY 5th Gen 36,000 BTU 230V#2 of 2Full review
The pricier of the two 36,000 BTU quick-connect units, with a better heating limit and quieter indoor unit than the Klimaire. Neither keeps much of its heat in deep cold.
Amazon $3,569.99 MRCOOL DIY Direct $3,790$3,569.9922,0008.5Quick-connect$162
