Just looking for advice re best way to set up the above system for a friend who is considering renovations for his large family. Plumber has advised that a condenser gas boiler could serve two showers. Solar panels could run another 3, but there would be no overlap ie those heated by gas would always be heated by gas. He currently has one electrical shower in situ and is considering keeping it as it was only recently installed. Any suggestions as to the optimal and most efficient set up. What type of tank would be needed ? Four bathrooms are upstairs and one on ground floor.