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
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.
The same labor required to install the sub-floor also installs
the radiant heat panels of the radiant hydronic heating
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 punctures.
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 carpeting.
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.
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.
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 left.
The cost for ECOWARM is $64 per sheet.