How deep in the concrete should radiant tubing be installed for floor heating applications?
The placement of the radiant tubing does not affect the performance or comfort in a typical four-inch basement concrete pour. Once the slab is warm, it is easy to maintain that heat. It is common practice to raise the radiant tubing in larger and thicker concrete pours (i.e., six inch and greater).
When installing snow melt hydronic for sidewalks and driveways, it is critical to have the tubing near the top as the temperature of the glycol (not water in case it freezes) hovers around freezing so it doesn’t take as long to heat up to start melting the snow. The radiant tubes only need to go above freezing for short periods of time as its only being used to melt the snow, not heat the atmosphere. It is still very important to insulate under the concrete so that the heat from the tubes focuses on melting the snow and not warming the ground. It is best to follow radiant heat manufacturer install instructions in any hydronic heat application.