My contractor replaced a 9000 BTU 10 SEER ductless system with a 20 SEER Inverter system rated 3000-12000 BTU. We are in the tropics, air temperature in the high 80's mostly, year round. I keep accurate records of power consumption and temperatures, and the new system uses about 70% as much power as the old, not half as advertised.
Old unit used 6 KW per day, new one about 4.3KW per day. At our very expensive power rates it adds up. Is this as would be expected, or might something not be working right. He already evacuated the system to humor me and weighed the charge to make sure it had come charged properly, and it had. It cools great and is quiet, just not as efficient as we had hoped. He had sold me on it using a chart from the manufacturer that claimed a 20 SEER would use 1/2 the power of a 10 SEER.