Mini Split Brands To Avoid . Ever since, mitsubishi has been the industry leader in innovation, new technology, and efficiency. Diy mini splits can provide heating in the winter as well (they are basically diy mini split heat pumps). Mrcool 36,000 BTU 3 Ton 16SEER Ductless MiniSplit Air Cond/Heat Pump from offerup.com A unit that weighs one ton with one indoor and one outdoor component with a 21 seer rating costs between $1,000 and $4,000, with the indoor mount type and brand most influencing the cost. Across the board, pioneer averages a 17.5 seer rating. Split system heat pumps are quite typical for many heat pump systems.