"R.P.McMurphy" wrote in message
...
I am turning a small box room into a wet room with a high flow shower.
However id like to keep running cost right down so am considering trying to
recover the heat in the waste water going down the plug hole to preheat the
cold water going into the thermostatic shower valve.

I cant seem to find any products for sale in the uk that do this, so am
considering making one myself.

Has anyone had a go at building one?

Steve

I'm thinking of the same thing myself, but don't know of any product. On
problem is that the waste water contain scum and hair, bits of soap etc, and
it's low pressure so cannibalising a boiler heat exchanger won't work. I'm
thinking of coiled microbore piping ( several in parallel ) inside a flat
box where the waste water can hang about for a few seconds. The other option
is to redirect the trap outlet so that it goes to a length of 40mm waste
pipe inside which some copper tube could be coiled for the cold water, the
40mm waste eventually conecting back up with the old waste outlet.

many configurations possible, all with small problems involved

Andy