Film for windows

[HowsTheSerenity]

Does anyone have that film that goes on windows that apparantly helps to keep the heat in the house?

Does it work?

Any idea what it is called and a recommendation for getting it?

Thanks

We used to use it before we got double glazing.

It does help to keep drafts out.

I think we bought it from wilkinsons and you stick it over the window and then with hair dryer you shrink it into place if needed.

Not sure what its called though.