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 installation.
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.
Easy Heat's Warm Tiles cables
are available as an off-the-shelf product in a growing
number of distribution channels, including retail.
Easy Heat also provides mats in stock and custom sizes.
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.
