If it helps, then the PV panels feed my whole house.
I could run the hot water heater and washing machine/tumble dryer all at the same time, but then i'd be using more than i'm generating, so I have to pick and choose which appliances are using the electricity wisely.
My domestic hot water system already holds 80 gallons of piping hot water before I even start.
Even if i exhausted all this, then provided I switch on the electric immersion heater during the day, (while the household solar panels are active) then I can get another 80 gallons of piping hot water maybe within 30-40 minutes, almost for free.
It's then just a matter of allowing the tub to maintain the temperature while its not being used.
During peak running my PV panels provide around 3kw.