I used the stuff; hated it. International Decorative Surfaces, a large laminate importer and distributor has it in for a few months and got rif of it "due to complications". And I had a lady call once who had not installed the DPM-like thing in her bathrrom and was feeling "shocks" when she walked on it with it on, and the floor was wet. Never heard from her after passing her onto AHT.
I think it was designed for under-carpet. But AHT pushed it into tile and laminate. Though really, cable or cable mat is for tile, carbon is for laminate and carpets.
Really though, who'd want to heat carpets?!?! All those bugs you're promoting the growth of with the extra warmth and all that. I have mild asthma and I couldn't cope with thinking I'm habouring MORE dust-mites.
Perhaps that's just my opinion though, I just wondered if you guys had experienced the stuff at all?