I have read a fair amount about the debate of above vs below subfloor application of radiant tubes. I have not seen any reference to products with aluminum built into the wall. They are claiming that heat diffuser plates are not required when using them (ie. pex-AL). After several hours reviewing the posts on this website, I find that hard to believe. Anyone have experince with these products, or an opinion. Is it possible to make a below floor application as efficient as above (assuming wood, no gypcrete or concrete; tile floor covering)? Is the difference that significant? Help, please