It's only for the odd non-dishwasher bit of washing up and for cleaning surfaces etc. so we think a Redring MS6, 1.5kW 6 litre one should be quite sufficient.
Our water pressure is within the MS6 specification so we don't need a pressure reducing valve.
However we will need an expansion vessel as the cold tap for the sink is (unsurprisingly) adjacent to the hot tap (well, it's a mixer). The specified expansion vessel:-
costs *more* than the water heater! That's really ridiculous.
I'm thinking of simply adding a loop of copper pipe to give the required 1.7 metre length that's required to avoid the need for an expansion vessel. 1.7 metres of copper pipe will cost a whole lot less than £75!
Is this a sensible idea?