I don't know whether people have come to the correct conclusions in this forum. I installed a 1 HP Fujitsu split system in my home about 8 years ago and also noticed on a plugin meter that it's drawing about 50 watts on standby, however at first power on in standby, the consumption is nil so there is clearly no heater involved. I am in Canberra where winter temps regularly fall below freezing. The standby power is only apparent after the A/C has been used and placed in off mode with the remote control. When the power plug is removed, a rush of gas can be heard in the unit so presumably this consumption is some kind of electronic non return valve, the unit is reverse cycle and under operation, consumption has been observed as low as 280 watts.
After unplugging from power and reconnecting straight away, this 50 watts is non existent until after next use. Repeat this process each time and you will resolve this problem.
It is an inverter type A/C.