Attic insulation
 

Apologies for starting a new thread when there are similar already in existence, but my question is a little more specific:

The latest issue of The Home Mag features two adverts for attic insulation, where foam is sprayed on the underside of the roof and, supposedly, reduces the temperature of the attic by eighty degrees (I wouldn't like to be up there in the winter) and your electricity bills by 50%.

Have you had this form of attic insulation put in, and did the results come anywhere near the claims? What did it cost?

Thank you