Thanks mclairs, for your sharing. We hope not to spend too much for this system 2. I already have system2 x 1 and system1 x 2 all panasonic in good condition. Not even sure if I need inverter since this system2 is for sharing with 1 bedroom (use 2hrs/nite) and living room (use a few hours/mth). Maybe a non-invertor can already?