Yes, but you need to check with your supplier if your electric shower or combi boiler can accept a pre-heated water supply. It's not a hot pre-heated supply (such as with a solar system) but more of a pre-warmed supply around 28°C.
Many brands of combi boilers and electric showers are suitable for this. If you are using it with an electric shower then choose one with manual power settings, such as turning down the power consumption to compensate for the pre-heated incoming water. Alternatively some people decide to achieve much higher flow-rates than would normally be possible with an electric shower, especially in the winter months.
It works very well with showers over a bath, which is a very popular solution in the UK.
However it will not work with the bath water itself, as with baths the consumption of hot water precedes the draining of the hot water; the two need to be happening in parallel - as in a shower.
The all copper construction of Shower Save is such that lime scale will not be a problem. At no point is the cold water in close proximity to hot water at 60°C or higher, which could result in limescale build up.
In effect the cold water passageway in the Shower Save acts as a 2m section of copper supply pipework.
In common with all heat exchangers Shower Save has separate water channels for grey water waste water and fresh water, so they never come into contact with each other.
Instead, the heat is transferred from the warm waste water to the cold mains water through a highly conductive copper wall, in a uniquely efficient way.
No, because it has un-treated water in it and could freeze (and should not be insulated).
The best installation location is for it to be boxed in next to the internal stack pipe.
Shower Save isn't insulated for two reasons: