Is the solar water heater on the balcony plugged in for electricity?

This depends on your own needs, in principle, solar energy does not need electricity, but because of the built-in electric auxiliary heating, so when there is no sun, you need to start the electric auxiliary heating hot water, this is the need for electricity, if you don't need to start, you don't need to be almost, but the corresponding can't see the real-time temperature! --Sanbin solar water heater.

Solar energy needs to be plugged in, otherwise the system cannot be operated, because both water and heating when there is no sun require electricity --- single-bin solar water heater.

If you look at what your solar energy looks like, if it is more intelligent, you should be able to set the mode, and under normal circumstances, it will not start the electric heater, so it will not use electricity. If it's simpler, then you may automatically heat it up as soon as you plug it in, which will be very power-intensive.