| Warm
water is circulated through a network of reinforced polyethylene
pipes laid in the floor at the time of construction. The underfloor
heating pipes are embedded within concrete or a sand/cement mixture,
which provides continuous thermal contact between the pipes and
the underside of the floor surface. The water is distributed to
the pipes through solid one-piece manifolds at between 35-55°C
and heats the floor surface to a temperature in the range of 22-27°C.
Heat is emitted into the room as approximately 60% radiant heat,
20% convection, and 20% conduction. Each room has its own circuit
and is individually controlled by a room thermostat. When the room
reaches its pre-set temperature the thermostat sends a signal to
an electrically operated valve on the manifold, closing that particular
circuit. The floor effectively becomes one large heat store giving
off a gentle, even, radiant heat to the whole room. |
Unlike
a radiator system, which you can programme to come on twice a
day, underfloor heating is always active, and is normally set
to achieve one of two target temperatures. When the building is
occupied, a temperature of around 21°C is programmed into
the system, while a setback temperature of around 17°C is
sufficient for night time or when the building is unoccupied.
Controlling in this way maintains comfortable even heat all the
time. Once the floor has become warm it takes a very small amount
of energy to keep it warm, whereas with a radiator system, the
radiators have to be warmed up from cold using very high temperatures
each time the system comes on.
A
fully automatic option allows you to program each room with its
own time and temperature parameters.
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There
are various ways to install underfloor heating, and here at Borders
Underfloor Heating we keep it simple. The simplest and most efficient
way is to have as much of the surface of our 17mm pipe in contact
with the thermal mass (the concrete or infill) as possible.
Some
companies use insulation with grooves for the pipe to be fitted
into, but this means that only the top curve of the pipe is giving
its heat to the floor. This doesn't make sense to us because the
entire surface of the pipe is capable of transferring heat to
the concrete.
Some
companies overcome this by fitting metal plates into the insulation,
but these are expensive and some can double the cost of your heating
system.
A
slab plus screed or beam and
block floor gives the best heat output and you can find floor
construction diagrams with links to illustrative photos here.
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