In-Floor Radiant Heating
In-floor radiant heating systems are low mass, modular board
underlayment systems. Instead of embedding the hot water tubing in
concrete, it's laid in the grooves of pre-cut wood panels. The low thermal
mass of wood, as opposed to concrete, allows for faster heat up times and is
more responsive to on-demand heating. Modular in-floor heating is ideal for
remodeling or new construction projects.
The tongue and groove panels come in various sizes and configurations to fit
different floor plans and can be sawed to fit where necessary.
One type of in-floor radiant hydronic system is sold under the WarmBoard
trademark. Each full size sheet measures 4' x 8' x 1 1/8" and is the only
radiant heat module approved by the ICC (International Code Council) to
double as a structural sub-floor.
The 16' x 48" (5.33 sq ft) panels are not intended for
structural use as sub-flooring but are glued, and then
screwed or stapled to the wood sub-floor.
3/8" PEX tubing, which circulates the heated water, is
snapped into pre-cut grooves in the panels as shown.
The heat radiates from the tubing to the wood and
aluminum covered modules.
InfloorBoard is applied to the sub-floor only where needed, not under
counters or other unheated areas. This usually means 20% fewer panels in
terms of square footage than an all in one sub-floor system.
Since InfloorBoard is applied later in the construction sequence, protecting
the tubing during construction is less of an issue.
The cost of InfloorBoard panels range around $4 per sq. ft.
ECOWARM radiant board is the newest product to enter the radiant in-floor
heating market and is similar to InfloorBoard in use and application.
The panels are constructed with non structural oriented strand board (OSB)
and topped with aluminum to distribute the heat.
The same labor required to install the sub-floor also
installs the radiant heat panels of the radiant hydronic
The installation sequence for WarmBoard requires the
PEX tubing to be inserted into the precut grooves
soon after the panels are affixed to the floor joists. In
the meantime, until the floor coverings are installed,
the tubing should be protected from accidental
All of the in floor systems mentioned here can be covered with laminate,
engineered wood, tile, vinyl, or carpeting. If carpet is your choice, all radiant
systems work best with a slab foam rubber carpet pad (SFRP). Apart from
having excellent heat transfer characteristics, SFRP is a superior cushion for
The cost of WarmBoard is slightly less than $7/sq ft for the board only.
InfloorBoard (brand name) modular panels are constructed of 5/8" thick
composite board covered with aluminum to help spread the heat evenly
across the floor.
Each sheet measures 23.5" x 47" x 3/4" thick, or 7.7
square feet per board, and is configured in straight
sections or return loop sections as pictured on the
The cost for ECOWARM is $64 per sheet.