Thermalboard Compared to Underfloor Radiant Heat Transfer Plates

 Lower material costs, but higher installation costs for underfloor systems

While the aluminum plates may only cost $1 / sq.ft, installing this type of system properly is extremely labor intensive. It is far easier and faster to install Thermalboard on top of the subfloor rather than beneath it. It’s also more heat efficient.

Life Cycle Costs: Much higher lifetime operational costs due to higher water temperature required.

Mechanical Operational Costs: Most radiant floor systems utilize a condensing boiler or water heater. The condensing in these heaters, which generate the cost savings, occur below a 135F degree exit temperature. If the radiant system requires temperatures higher than 135F, then the actual heat source efficiency drops to about 85%.

The premium price you paid for the condensing heat source is lost and your energy bills will be higher. Underfloor systems often require water temperatures above 135F, further increasing the life cycle cost of your system. Lower temperature equals lower costs — and better comfort!

Design Performance Issues with Underfloor Systems:

• Response Time: While underfloor plate systems deliver heat from under the floor, through the subfloor, then up through the flooring goods (hardwood, carpet, tile, etc.) Thermalboard is installed immediately under the floor, resulting in much faster response time for heat delivery.
• Noise: There is a long history of underfloor aluminum plates making irritating expansion noises when turning on the system. These sounds occur when the required high temperatures come into contact with cooler plates. Proper installation is critical and seemingly evasive. You should also use weather responsive controls to lower the supply water temperature when employing this application to avoid high temperatures shocking the system.
• Insulation: It is critical that one installs 2 or more inches of foam board under these systems with zero infiltration leak paths. Fiberglass batt is neither effective or durable in horizontal subfloor application. Meticulous installation that avoids “points of infiltration” is critical in lowering the already higher heat loss of these systems.