Electric Radiant Floor Warming - the Affordable Luxury
Mountain climbers have an old saying: "Don't cheat your feet."
A homeowner might consider this advice when building or remodeling
a bathroom or kitchen floor.
For floors, homeowners know that ceramic, slate or marble tiles
and wood laminates are attractive and durable alternatives to hardwood,
carpet or vinyl. They want the beauty of tile floors, but their
feet tell them they're cold. While most people are comfortable with
air temperatures of 65 to 75 degrees, they tend to feel uncomfortable
if there's more than a 5-degree difference between the surface temperature
(80 to 85 degrees) of the head and that of the feet. A bare foot
gives an immediate indication as to the comfort level of any floor.
For this reason alone, tile is often not the flooring of choice.
With a tiny amount of heat supplied by a human foot, carpet fibers
warm almost instantaneously to "foot" temperature, about 83 degrees.
A ceramic tile can't compete in this race: its mass needs a lot
more heat for a longer amount of time. It would take approximately
30 minutes for a human foot to increase a 68-degree marble floor
to foot temperature!
Radiant floor warming systems solve this problem -- fast! The most
common radiant floor warming systems are either hydronic (circulating
hot water in tubes under the floor) or electric (heating cables
under the floor).
Hydronic systems are more complicated, requiring pumps and valves
and modulators and so on, and, as a result, are a lot more expensive
to install than electric. Still, for whole house heating solutions,
hydronic systems are a good choice.
By contrast, electric systems are inexpensive enough for single
room applications and simple enough for handy do-it-yourselfers
to install. Suitable for new construction or remodeling applications,
many electric floor warming systems include a network of cables
installed in the mortar just below the tiles. These cables gently
warm the tiles, operating on ordinary house current. While using
a professional electrician is advised for those not comfortable
working on electrical installations, these systems are generally
easy to install and will not compromise the integrity of the tile
Designing a floor warming installation first requires a determination
of the area to be warmed. Calculating the total square footage will
require collecting information from the blueprints of the room or
actually measuring the area itself. It should be noted that areas
that are inaccessible or under vanities, cabinets, or plumbing fixtures
should not be included -- there's no need to heat floor area that
won't be walked on!
When making the calculations it is advisable to design a layout
that considers actual use and traffic patterns in the area to be
warmed. Using care in measuring and calculating the area will help
ensure that the proper cable is selected for the installation. Preformed
mats can also be selected to simplify the installation, but cable
systems have the advantage of providing better area coverage.
Programmable thermostats, available with setback features, help
ensure that the cables are only heating the floor when the homeowner
desires. Floor heating thermostats differ from room heating thermostats
in that they have a sensor that extends down into the floor to sense
the actual floor temperature, and to control the cables' output
accordingly, usually at about 85 degrees. Today, floor warming thermostats
are available with sophisticated programming features as well.
A complete system often can be installed using an electric drill
and other ordinary hand tools. The installation process can be completed
in three phases that will likely correspond with the construction
or remodeling phases of your home or building.
Phase one -- Electrical Rough-in
During the electrical rough-in, the electrical box for the thermostat
is installed, and the power supply cable pulled into it. Conduit
holes are drilled into the wall plate (a two-by-four on the floor
at the bottom of the wall) to enable the heating cable leads and
thermostat sensor to be pulled into the electrical box.
Phase two -- Install Cables
For new construction, the cables are installed only after the drywall
is finished and immediately prior to the tile installation. The
cables are provided with plastic strapping that is stapled to the
floor, and the heating cable is simply woven over the floor on the
strapping. The leads of the cable and the thermostat sensor are
routed through the conduit holes and up to the electrical box.
Phase three -- Apply thin-set mortar and install floor
A "scratch coat" of mortar (just enough to cover the cables) is
then applied and allowed to dry, usually just a day. Then, the flooring
can be completed in the usual manner.
Phase four -- Thermostat and Power Connection
The last phase calls for the installation of the thermostat and
connection to the power source.
Courtesy of ARA Content