At least in Germany that's already the standard plumbing practice: a mixing valve on the tank outlet ensures the tap temperatures are safe. This is important be

At least in Germany that's already the standard plumbing practice: a mixing valve on the tank outlet ensures the tap temperatures are safe. This is important because the tank is required to periodically heat to 65C to kill legionella bacteria, and with solar input can heat to as much as 85C, so without such a valve the tap temperature would be unpredictable and sometimes dangerous.