Add-ons to recover energy from combi gas boiler exhaust?

Hi All,

We have a relatively new  combi gas boiler.  Even though new (Worcester model installed 1 year ago), I am surprised to find out that having exhaust gas temperatures of around 50degC pumping out into the atmosphere is normal.  Strikes me as a heck of a waste of energy.

I have seen that Worcester themselves make an add-on for the flue pipe that can be used to recover some energy from this, but they themselves don't seem to think it is worthwhile - and it is pretty expensive at close to £1000.

Has anybody got experience of fitting some kind of heat exchanger to the flue pipe of a gas boiler?  There are no doubt implications in terms of proper function of the boiler and warranties etc, but it just seems crazy to chuck out such hot air!

Thanks,
Ralph