Heat 4 spaces at once with the MrCool DIY 36k BTU 21.5 SEER 4-Zone Ductless Heat Pump Split System–9k+9k+9k+9k. This is a multi-zone, powerful air conditioning and heating solution that you can install on your own. The outdoor heat pump for this system has a heating capacity of 36,000 BTU and is highly efficient with a SEER rating of 21.5. This is thanks in part to the variable speed DC inverter. All 4 9,000 BTU air handlers can manage the room temperature of areas up to approximately 375 sq. ft. Color: White.