Warmboard-S vs Gypsum Concrete

The Most Important Comparison is Conductivity:WHY? Simply put, the job of a radiant panel is to conduct heat from water in a tube to the surface of your floor. Gypsum concrete may have a long association with radiant, but given a blank sheet of paper today, no engineer would choose that material for a radiant panel. It is a poor conductor and its high mass cannot accurately respond to your changing heating needs. Warmboard’s high conductivity and low mass mean:

  • Floors are more evenly heated and the system responds more quickly and accurately to satisfy your ever changing heating needs. Both of these performance qualities are essential to your comfort
  • The water in those tubes can be much lower in temperature, saving energy and significantly extending the life of all the equipment in your heating system
  • Your investment in beautiful hardwood flooring is protected through even floor temperatures, secure fastening and comparably dry material under your hardwood
  • Tubing can be more widely spaced, saving on tubing, manifolds, controls and all the labor to install these components in your system

There’s a reason that frying pans are made of thick aluminum and not concrete; conductivity is key when it comes to fast heat.

Five Times the Conductivity:

It’s an undeniable fact that the thick, aluminum plate that covers the entire surface of Warmboard is five times more conductive than a typical gypsum concrete slab.

Yes, Warmboard costs a little more, just as all superior products do when compared to inferior ones. But as part of a complete radiant system, that premium is small while the conductivity improvement is substantial! It is rare that a consumer is given an opportunity to choose between similarly priced products, one of which outperforms the other by 500%!

Does Not Apply:

The following list of considerations applies to a gypsum-based radiant system, but not Warmboard-S.

  • Additional subfloor installation
  • Increased amount of tubing, manifolds, controls and the labor to install them all
  • Sealant to protect porous gypsum concrete from damage
  • Addition of pressure treated bottom plate for all walls
  • Upsized floor joists for increased weight
  • Addition of nailing strips or floating plywood overlay in order to achieve nailed in place hardwood flooring
  • Vacation home may require remote communication system to heat home a day or more prior to your arrival
  • Higher water temperatures: 110–150ºF (43–65ºC) compared to 80–120ºF (26-49ºC) with Warmboard-S

Performance You Can See:

These thermographic images (below) will help you better understand the very real and significant differences in performance between a gypsum slab and Warmboard. The panels in this study were tested side-by-side with identical air temperatures, water temperatures and floor coverings. The differences are obvious. Higher output, more even floor surface temperatures and much, much faster response, make a powerful case for high conductivity, low mass Warmboard.

After 30 minutes, the gypsum concrete is only producing 1 BTU/sf, while Warmboard is already producing 10 BTUs/sf.

After 2 hours, 30 minutes, gypsum concrete is producing 10 BTUs/sf, while Warmboard is producing 19 BTUs/sf, with more even heat.