Hi There...we're building a home with all radiant heating and think we've decided to use Warmboard on the upper levels where we will have hardwoods installed. In the basement, we definitely want to use carpet so are concerned about the transmission of the heat through the pad and carpet itself. Would you pros recommend using some kind of panel system (like Roth) over the slab to improve this situation or would you just go the conventional route and install it in the slab? Thanks in advance for any insights....

The tubing goes in the slab.

Any thermal resistant material between you and the tubing decreases system efficiency (hotter water, more pumping). As concrete has virtually no thermal resistance it is nearly the perfect radiator.

The carpet and pad should be considered by your radiant floor heating designer, who will also be concerned about floor coverings over Warmboard® or any radiant panel. Carpet is used over radiant floor all the time but will decrease operating efficiency and is never recommended in basements. Special care must be taken when carpeting a basement floor, including insulation and an adequate vapor barrier.