Radiant Floor Heating
|Interest has increased in radiant floor heating with the
introduction of nonmetallic tubing and new design, application,
and control techniques. Whichever method is used for optimum
floor output and comfort, it is important that the heat be
evenly distributed over
the floor. Spacing is generally 4 to 12 in on centers for
the coils. Wide spacing under tile or bare floors can cause
uneven surface temperatures.Embedded Piping in Concrete Slab.
Plastic, rubber, ferrous, and nonferrous pipe and tube are
used in floor slabs that rest on grade. The coils are constructed
as sinuous-continuous pipe coils or arranged as header coils
with the pipes spaced from 6 to 18 in. on centers. The coils
are generally installed with 1.5 to 4 in. of cover above them.
Insulation is recommended to reduce the perimeter and back
losses. Figure 20 shows the application of pipe coils in slabs
resting on grade. Coils should be embedded completely and
should not rest on an interface. Any supports used for positioning
the heating coils should be nonabsorbent and inorganic. Reinforcing
steel, angle iron, pieces of pipe or stone, or concrete mounds
can be used. No wood, brick, concrete block, or similar materials
should support coils. A waterproofing layer is desirable to
protect insulation and piping.
Where coils are embedded in structural load-supporting slabs
above grade, construction codes may affect their position. Otherwise,
the coil piping is installed as described for slabs resting on
The warm-up and start-up period for concrete panels are similar
to those outlined for plaster panels.
Embedded systems may fail sometime during their life. Adequate
valves and properly labeled drawings will help isolate the
point of failure.
Radiant floor heating can be installed in any new or existing
building. Residential, commercial, public, or agricultural. It
can be installed in concrete or suspended wood floors.
Although hot water can be used with virtually any type of heating
system, including forced air and baseboard, we want to talk specifically
about radiant floor heat. Whether you are planning new construction
or want to improve comfort and reduce costs by updating the heating
system in your existing home, business, church or any other facility,
you should consider the advantages of installing a radiant floor
heating system. With this heating system, heat radiates from the
Advantages Of Radiant Floor Heat
No Cold Spots:
With Radiant Floor Heating, heat radiates from the entire floor.
You get a warm floor and even heat without hot or cold spots.
Quiet and Invisible:
Radiant Floor Heating is the invisible heating system. You can't
see it, you can't even hear it. There's no fan, no ducts in the
floor and no radiators along the wall.
With no radiators or duct work to attract and trap dust you'll
have less cleaning and there won't be any germs, allergens or
Radiant Floor Heating does not dry out the air like a forced air
system and there is less heat loss when doors are opened in the
winter. You can even open windows for ventilation without significant
heat loss. People with allergies have fewer problems with floor
The human body temperature is the highest in the head and circulation
is poorest in the feet. Look at the Ideal Heating Curve for the
The human body is most comfortable with a
temperature of 75 degrees F at our feet and a temperature
of 65 degrees F at our head. With this temperature curve
our feet and bodies are warm while our head is slightly
cooler. We feel warm, comfortable and alert.
Now, look at the Radiant Floor Heating Curve - . Radiant
floor heating is the only heating system that gives you
a room temperature curve that matches the Ideal Heating
Curve for the human body. Warm at the floor and cooler at
our head. Chart illustrates the room temperature curve you
get with forced air heating. It is the exact opposite of
what the human body requires. With forced air we can have
cold feet, an uncomfortably cool body and we feel tired
because the air is too hot in the top half of the room.
Long heat up period
Requires major disruption on existing buildings
Long cooling down period
Cannot respond rapidly to quick temperature changes
Choice of floor finishing requires careful consideration
Changes of floor finish may affect performance
So-called "wet" installations embed the cables
or tubing within a solid floor and are the oldest form of
modern radiant floor systems. The tubing or cable can be
embedded in a thick concrete foundation slab (commonly used
in "slab" ranch houses that don't have basements)
or in a thin layer of concrete, gypsum, or other material
installed on top of a subfloor. If concrete is used and
the new floor is not on solid earth, additional floor support
may be necessary because of the added weight. You should
consult a professional engineer to determine the floor's
Thick concrete slab systems have high heat capacity
and are ideal for storing heat from solar energy systems,
which have a fluctuating heat output. The downside of the
thick slabs is their slow thermal response time, which makes
strategies such as night or daytime setbacks difficult if
not impossible. Most experts recommend maintaining a constant
temperature in homes with these heating systems.
Due to recent innovations in floor technology, so-called
in which the cables or tubing run in an air space beneath
the floor, have been gaining in popularity, mainly because
a dry floor is faster and less expensive to build. But because
dry floors involve heating an air space, the radiant heating
system needs to operate at a higher temperature.
Ceramic tile is the most common and effective floor covering
for radiant floor heating, as it conducts heat well from
the floor and adds thermal storage because of its high heat
capacity. Common floor coverings like vinyl and linoleum
sheet goods, carpeting, or wood can also be used, but any
covering that helps to insulate the floor from the room
will decrease the efficiency of the system.
If you want carpeting, use a thin carpet with dense padding
and install as little carpeting as possible. If some rooms,
but not all, will have a floor covering, then those rooms
should have a separate tubing loop to make the system heat
these spaces more efficiently. This is because the water
flowing under the covered floor will need to be hotter to
compensate for the floor covering. Wood flooring should
be laminated wood flooring instead of solid wood. This reduces
the possibility of the wood shrinking and cracking from
the drying effects of the heat.
|Dry system radiant flooring
|Electric Radiant Floors
|Floor Heating Control