> It's well known that new double glazed windows have a compatively long
> payback
> period, although the advertising would have you believe otherwise. However
> if
> you need to replace a rotten window, then make it double glazed anyway, as
> the
> incremental cost in that case is low and will pay back in more like 5
> years (or
> less). Check out local suppliers too rather than rely on higher priced
> national
> companies.