GH recently attended a product information session for Warmboard, a radiant panel product that we will be using at our deep energy retrofit project in East York. Warmboard consists of an engineered wood sheathing panel (either OSB or plywood) with a sheet of aluminum applied to one side. The panels are contoured with grooves that receive hydronic tubing with a tight friction fit. Warmboard custom makes the panels based on the mechanical design (which they can do in-house if desired) with the specified spacing and layout. The panels are numbered and delivered with shop drawings for easy installation on site. In the eventuality that a panel needs to be field modified (something always comes up!), a tool set is provided so that additional grooves can be made on site.
The OSB panel is for retrofit installations, whereas the plywood panel is suitable for structural applications. In a new build, this allows for the installation of a hydronic-ready subfloor in one shot. Any flooring approved for use in a heated application can be used with Warmboard. For nailed-down hardwood, flooring nails penetrate the soft aluminum and the tubing is clearly visible making it easy to avoid.
According to the manufacturer, the advantages of Warmboard over other products is a very fast and even distribution of heat throughout the panel thanks to the aluminum skin. This makes for a more efficient and comfortable installation. Compared to a light-weight gypsum pour on a wood-framed floor deck, we also thought there’d be a scheduling advantage as the pouring and cure time are avoided.
An interesting application of the product presented by the Warmboard representative was its use as a radiant wall panel. In retrofit situations, you could eliminate your bulky cast iron radiators and install Warmboard behind wainscotting – freeing up floor area and enhancing the finish of a space.
Although the design has not been finalized, at our East York project another unconventional use of the product has been specified – as a radiant ceiling for heating and cooling. In this application we’d install the retrofit panels on the ceiling and cover them with drywall. We’ll have to take extra precautions while boarding as large areas (and the tubing they contain) are obscured at a time. The primary advantage of a radiant ceiling over a floor is that there is less potential for obstructing the radiant surface with furniture, carpets, etc. In a cooling application, there’d also be a convection effect as the air cooled by direct contact with the surface falls to the room below.