If you want get fancy then get second thermostat - bit of fiddly wiring
etc - but then you could place one 1/3 from the top - and used during
the day - set at a temp when you only need a little h/w for hand
washing etc and the other nearer the bottom which you can use when
baths etc are needed

Would require some extra time clock contacts etc - but worth a thought

In the days of green house gases this could save tones of CO2