ThermalStar Radiant Comfort panels from Atlas EPS provide insulation and an easy way to install under-floor hydronic heat for both new construction and retrofits. The expanded polystyrene panels have grooves that hold the hydronic tubing without the need for fasteners. New-construction panels install under slabs, while retrofit panels are thinner and install between subfloor and finished flooring. The panels come with a limited lifetime warranty for physical and thermal performance. Pricing varies.