Instructions / Assembly

SunTouch UnderFloor is a safe and
efficient electric floor-warming prod-
uct for interior applications. It is intend-
ed only for installation under a wood
subfloor in residential and light com-
mercial installations. It is not designed
for other purposes such as roof snow-
melting. Any use or installation of this
product other than what is stated in
this installation manual will void the
Limited Warranty.
SunTouch UnderFloor is designed
to deliver approximately 10 watts/sq.
ft. of floor area. The temperature of the
warm floor is dependent on how well
the floor is insulated, as well as the insu-
lating value of the flooring materials.
If the joist space is sealed against air
leakage, exterior rim joists are insulated,
and the underneath side of the floor
is insulated, most floors can be heated
up to 15°F warmer than they would
otherwise be. Due to the insulating
value of carpet, carpeted floors may not
achieve the same temperature rise. The
floor may or may not achieve this tem-
perature rise, and no representations
are made regarding the performance of
any system.
For best results, install unfaced fiber-
glass R-19 or R-13 (or equivalent) below
the mat. Do not insulate below the mat
with more than R-19, and no more than
R-11 total on top of the
subfloor, including all floor coverings,
rugs and other items placed on top.
SunTouch UnderFloor can be used to
heat a room, as well as warm the floor,
provided the heat loss of the room
falls within the mat’s capabilities. A
designer must determine if the out-
put from the SunTouch UnderFloor is
Shielded
power lead
INSULATION
(MINIMUM R-13)
SunTouch UnderFloor
™
mats are only intended for installation
below the subfloor.
Shielded power leads make for a tougher and
safer connection to the controls.
2 SunTouch UnderFloor Installation Manual
Introducing SunTouch
®
UnderFloor
™
enough to match the heat loss of the
structure. Refer to page 3 for helpful
design guidelines.
The SunTouch UnderFloor Mat
The mat is composed of a heating
cable, a foil “radiator” to make a radiant
surface, and a set of power leads for
connection to the floor-sensing control.
These mats are manufactured in sizes
suitable to heat joist bays spaced 16” on
center. Mats are rated 120 VAC. Select
the mat length to fit into the joist space
available. Multiple mats can be used to
fill a larger area, however they must be
wired together in parallel (not in series)
if they are to be connected to the same
control. NEVER supply 120-VAC mats
with 240-VAC.
Visit the SunTouch Web site at www.
suntouch.com/diy, or call 888-432-8932
if there are any questions regarding
the installation of the mat or its related
electrical components.
Subfloor
UnderFloor mat
(with 2” air gap
above the mat)
Insulation
Floor joist
Cross section of typical
UnderFloor installation