I picked up one of these water/energy saving packs at Sainsburys
today: http://www.littlefoot.co.uk

It has a "Water widget" which claims to "Save £100 on your utility
bills". There is no justification for that figure of £100 the website.
I've fitted it and there is no noticeable difference to the shower
flow. Since I have a combi boiler I presume the water will heat up
more quickly. Or will the cold sucked-in air make the water colder?

Has anyone fitted one?

Any comments?

It makes a really annoying whistling sound. The missus isn't going to
like it.