Eric provides a detailed explanation of the radiant heating system using aluminum plates with PEX tubing and a stainless steel radiant manifold. The system circulates warm water through the tubing, heating the aluminum plates that are in contact with the subfloor. This radiant heat is then dispersed through the subfloor, heating the area above. The system allows for even heat distribution and is controlled by zone valves for different areas of the house. Although it may require slightly more energy compared to other systems, the decision to install it underneath the floor was made to avoid altering the floor heights and overall house design. Overall, it's an efficient and effective way to utilize hydronic heating for a comfortable living space.