Post on 28-Apr-2015
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UNDERFLOOR HEATING SYSTEMS LTD
PO BOX 445
WORCESTER
WR3 8YN
TELEPHONE…01905-616 928
FAX………….…01905-616 928
EMAIL…………info@underfloorheatingsystems.co.uk
WEBSITE………www.underfloorheatingsystems.co.uk
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CONTENTS
1. WHY UNDERFLOOR HEATING?
2. FREE QUOTE DESIGN SERVICE
3. THE PIPE
4. BENEFITS OF UNDERFLOOR HEATING
5. FLOOR CONSTRUCTIONS AND PIPE LAYOUT
5.1 Concrete Floor Constructions
5.2 Timber Suspended Floor Constructions
6. CONTROLS
6.1 Control Partnerships
7. GUIDELINES FOR THE DESIGN AND INSTALLATION OF THE
UNDERFLOOR HEATING SYSTEM
8. CONCLUSIONS
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1. WHY UNDERFLOOR HEATING?
We now spend an increased amount of time indoors. The majority of the population
now spends at least 22 of every 24 hours in some kind of artificial climate.
Underfloor heating is far from a new concept, it was first used by the Romans. Their
dwellings were constructed with voids through which air, warmed by an open fire,
would pass, thus heating the structure.
Underfloor heating is not a new concept in this country either. In the past electric
heating elements were buried within floor screeds. These were heated over night
using 'cheap rate' electricity. The main fault was the uncontrollability, the building
would over heat during the day but in the evening, when heat is generally required,
no further heat was available. Electric elements are also very expensive to run.
With today's modern multilayer pipes, control systems and high efficiency boilers
the underfloor heating systems of today are extremely comfortable and
controllable. No longer will unsightly radiators take up room space create hot
and cold spots in the house and circulate dust.
Underfloor heating from the whole floor area of the house gently warms the air
above, eliminating cold spots. The warm air convects from the floor surface losing
approximately 2 degrees centigrade at 2.0 meters above the floor, which makes the
system ideal for all ceiling heights.
Independent tests reveal that the most acceptable indoor climate is one in which the
floor temperature ranges between 19-29°C and the air temperature at head level
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ranges between 20 and 24°C. With radiator or convector heating systems a vertical
temperature gradient is produced; colder at foot level than at the head.
A modern indoor climate surely demands a heating system which will match the
required conditions for human thermal comfort with the principal heating effect
being evenly distributed at ground level and not above head level.
Modern building techniques including improved levels of insulation, double glazing
etc., have improved the U-valve (the measurement for a buildings heat loss)
dramatically for our buildings. Heat source technology has also taken a leap
forward with the introduction of heat pumps, condensing boilers, solar panels, night
storage systems etc. It is worth noting that all these innovations operate at higher
levels of efficiency when linked to a low temperature water distribution system.
Underfloor heating has made it possible to reduce energy consumption by using low
water temperatures. These systems, based on the development of complex and very
high quality plastic pipe, such as the multilayer pipe, now account for over 60% of
some European heating markets.
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2. FREE QUOTE AND DESIGN SERVICE
Underfloor Heating Systems Ltd offers a free quote service for any project. All we
need is a drawing of the property to be sent to us by post, fax or email. The price will
include the complete package for your underfloor heating system.
When the project is ordered we will also offer a free hand sketch on how to lay the
pipes. An AutoCad drawing of the pipe loops can be ordered for a small extra
charge. But in most cases the hand sketch does the job.
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3. THE PIPE
Multipipe multi-layer pipe systems now offer the most comprehensive range of
plumbing and heating systems available.
Used extensively throughout Europe, Multilayer pipe is both flexible and formstable. Its
enclosed aluminium pipe ensures that multilayer pipe is 100% oxygen diffusion proof
while maintaining very low expansion rates similar to other metal pipes.
The inner and outer polyethylene pipes prevents scaling and corrosion and its unique
combination of butt-welded aluminium and crosslinked polyethylene ensures that
multilayer pipe is the only full strength plastic alternative to copper. Multilayer pipe
gives the installer the advantages of both metal and plastic, but with the disadvantages of
neither.
Offered with fittings ranging from standard compression to the superb "Press-fit"
system, multilayer pipe brings new and genuine improved standards to installation
techniques. Currently available in 7 sizes, multilayer pipe is now the first genuine pipe for
all applications, be it plumbing, heating, underfloor heating or mains supply.
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1. Butt-welded aluminium pipe.
2. 100% oxygen-tight and water vapour diffusion tight.
3. Low coefficient of linear expansion.
4. Entirely corrosion-resistant, also against chemicals and electrochemicals.
5. Sound-insulation similar to entirely plastic pipe.
6. Electro-beam crosslinked inner and outer pipe.
7. High resistance to pressure and temperature.
8. Smooth surface, less loss of pressure.
9. Light as plastic piping.
10 Flexible, easy to bend even at low temperature, retains curved shape.
The small bending radius, maximum flexibility and stability of multilayer pipe
make for a rapid, economical and reliable installation.
The multilayer pipe can quickly and easily be used in conventional radiator
installations. Fittings are available to suit system designs or a central manifold
system.
Being an attractive matt white finish the short leg to radiator valves does not require
decorating. The pipe is light weight and supplied in coils, which make
transportation and handling easier.
There are 10 reasons why multilayer pipe is the best available pipe for underfloor heating:
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There are a number of features and benefits that occur from underfloor heating.
Space & Economics
Every square metre of your home can be fully utilised and the cost for our system is
very similar to a radiator system.
Hygiene
No dust and the underfloor heating will help to reduce house dust mites which is a
benefit to asthma sufferers. Moisture content is too low, to support dust mites.
Aesthetics and Labour saving
You can design your home to suit your needs rather than that of your heating
engineer. Cleaning of the floors is easier and wet floors dry very quickly. Prevents
discolouration of paintwork, peeling of paper etc.
Comfort
Radiant heat will provide the highest comfort levels at an even temperature
throughout.
Silence
Compared to radiator systems, there is no noise. No annoying ticking as pipes
expand in floor voids.
Cost effective
It has been proven that energy saving from 15-40% can be achieved with underfloor
heating.
Ease of control
Small temperature between the floor surface and the air above means the system is
practically self regulating.
4. BENEFITS OF UNDERFLOOR HEATING
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The Underfloor Heating system can be fitted in both concrete floors and timber
suspended floors. For other floor constructions please contact us and we will
explain the installation procedure. for example we also offer a floating floor solution.
5.1 Concrete Floor Construction
In concrete screeded floors, the screed acts to diffuse the heat across the surface
providing an even temperature at the floor surface.
Depending on the type of building, construction, standards, there are a number of
methods of laying the underfloor heating pipes in concrete floor structures.
The most popular method of installation is as follows:
A concrete slab (or suspended beam and block construction) is laid over a damp
proof membrane. A 20mm thick piece of insulation is fixed to the perimeter
(external) walls, to a height to include the depth of floor insulation and screed.
5. FLOOR CONSTRUCTIONS AND PIPE LAYOUT
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Whilst the edging insulation may be on show it is covered by wall plastering and
skirting boards.
Floor insulation is laid to the whole area, joints are taped to prevent the ingress of
screed between the insulation boards. The floor is now ready for the underfloor
heating pipework installation.
We recommend you use a 50mm layer of Polyurethane insulation. If there is not
enough space for 50mm insulation, 30mm is recommended. We recommend
Polyurethane as it out performs Polystyrene and its greater density allows use of clip
fittings.
If you use polystyrene insulation (50mm) it is recommended that you install wire
mesh on top of the insulation and tie the pipe to the mesh. For other floor
constructions please contact our technical department.
The underfloor heating system should be installed as below.
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The pipe is laid at 200-300mm centres dependent upon design. Care must be taken
to protect the pipework whilst installing the screed. Finally the floor finish is laid.
Underfloor heating works well with almost any floor finish; tiles, carpets (use
carpets with a resistance of less than 0.15 m2K/W), timber floors, plastic etc. The
floor coverings and the adhesive must be suitable for the temperatures that
underfloor heating will provide, the maximum temperature they need to resist is
40°C.
Always check with the manufacturer of the floor covering if it can be used for
underfloor heating. Timber floors need to have a moisture content below 10% to
avoid shrinkage. The system must be operated for 21 days with a very low
temperature to dry the screed, then the floor covering can be laid. Also note that the
5.2 Timber Suspended Floors Construction
Timber suspended floors do not conduct heat as efficiently as screeded floors. This
means that the heat output is less.
Some manufacturers use heat emission plates to try to achieve an even temperature
on the floor. This is a very expensive way of installing underfloor heating in timber
suspended floors and at the end of the aluminium plate the temperature is not going
to be very high. Clearly there should be a cheaper solution that works without using
the very expensive aluminium plates. After all, the first floor is usually timber
suspended and on the first floor less heat is usually required. Also note that the first
floor is supplemented by heat from the ground floor.
Our underfloor heating system is very simple and easy to install in timber suspended
floors. The system is based on hundreds of installations that are now working with
total satisfaction.
Between the joists, a 50mm polyurethane insulation board is cut for a tight fit. It is
advisable to use scrap battens from the building site to support the insulation from
below.
screed must be allowed to dry for 6 weeks before the underfloor heating is operated.
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The pipe is then clipped on the insulation with our special pipe clips. Then the floor
boards are laid on top of the joists. Be careful not to leave too much air space
between the insulation boards and floor boards (25mm is recommended). The joists
need to be notched where needed for pipe runs.
For ground floor timber suspended or buildings 20 years or older we recommend:
To get the timber suspended floor to act as a screeded floor and to give out more
heat, the air gap between the insulation and the floor boards should be filled with a
lightweight screed mix. This infill is normally required for older buildings.
Underfloor Heating Systems Ltd highly recommends the infill for all ground and
first floor applications if the building is not built to current building regulations. The
mix consists of a 10:1 sand/cement or 8:1 'Lytag' lightweight aggregate/cement mix
on top of the insulation, with enough water to hold the mix together. The additional
load imposed on the floor by the mix is approximately 18kg/m2 for sand/cement
mix. Note that the mix is not intended as load bearing, merely as a heat conductor.
The thickness of the mix should be 25mm with the pipe included in it.
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6. CONTROLS
Controls options
There are many ways of controlling the underfloor heating. First of all, almost any
boiler can be used for underfloor heating. The most energy efficient system is to use
underfloor heating and a condensing boiler. Note, if the underfloor heating system is
going to be used with a combination boiler, always check with the boiler
manufacturer that the flow can be fitted with a secondary pump.
Self regulated
Underfloor heating is self regulating if the building is properly insulated. Heat
output is dependent on the temperature difference between the floor surface and the
room temperature.
For underfloor heating the temperature difference is very small between the floor
surface temperature and the air temperature, even a slight change in room
temperature significantly alters the temperature difference and the underfloor
heating compensates accordingly.
A practical example would be a dining room. First the dining room is completely
empty and then when dinner is served, there are many people in the room giving out
heat. The underfloor heating will automatically reduce the heat output and the warm
water will simply heat another part of the building.
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Control units
The building can easily be divided into two or three zones. For example a house
with concrete floors on the ground floor and timber suspended floors on the first
floor, could easily be controlled as two zones.
As generally there are two different floor constructions, the underfloor heating
system will need to provide different temperatures and different running times for
the floor constructions. This is best achieved with control units.
Beside each manifold, a two part motorised valve, a pump, a mixing valve and a
programmable room thermostat is installed. We can provide a premade control unit
for each floor or the control unit can easily be made up by the installer.
Note that the control unit is always required when you mix underfloor heating and
radiators in a building.
Manifolds
At the centre of the underfloor heating system is always a manifold. All the
pipework in the building is brought back to a central distribution point, which is
called the manifold.
The flow and return is taken from the manifold back to the heat source of the
building.
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The manifold comes with many useful items to help during installation of the
underfloor heating system:
• Return manifolds fitted with two-purpose control/balancing valves.
• Unit fully assembled, leak-tested and packed
• Wide range of accessory options.
• Both trunk ends with flat-sealed joints (nut and gasket) for safe, quick and easy
installation.
• Supply and return manifold are each fitted with an isolation valve and a
purge/vent valve assembly.
• Supply manifold fitted with circuit flow meters for accurate and easy balancing
and visual flow indication.
• Minimised depth dimension allows flush-wall enclosed cabinet mounting.
• Control valves are designed to accommodate standard actuators.
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Mixing valves
High flow, thermostatic blending valve for underfloor heating applications.
These valves are suitable for blending the flow and return to achieve a stable system
temperature, in systems up to 250 sqm. The thermostatic wax element ensures stable
mixed water temperature with quick reaction to supply temperature changes.
Individual room controls
The Underfloor Heating Systems Ltd manifolds are supplied with thermostatic
options. This means basically that on the return manifold, actuators can be mounted.
The actuators act on an on/off basis and they are connected to an air thermostat in
each room. The room thermostats and the actuators are 220-240V.
Underfloor Heating Systems Ltd do not recommend individual controls in the
bathrooms as these rooms often require hot water to circulate through the loops to
dry the floor. One loop should always be manually regulated.
Bathrooms, WC and En-Suites are usually the warmest rooms in a building. The
underfloor heating system does not cover a lot of floor area in a bathroom, so the
system might not provide enough heat. Therefore it is highly advisable to install a
towel rail or a radiator in the bathrooms, to provide extra heat. This can either be
connected to your underfloor heating system, hot water system or electrics.
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Filling the underfloor heating system
The system should be filled with water and fully vented of air. This can best be
achieved using mains water pressure through the two end caps on the manifold. All
valves should be closed and the flow end cap connected with a hose to mains water,
with the return end cap connected to a hose laid to a waste water point.
One by one the flow and the return valves are opened and closed on loops purging
them of air. When this is completed and the end caps are closed off, the pumps
should be run for five minutes and the air vented again at the end caps until all air is
bled from the system
6.1 Control Partnerships
Underfloor Heating Systems Ltd finds it vital to create partnerships in the HVAC
industry with underfloor heating controls manufacturer. We are proud to say that all
the water controls are supplied by Reliance Water Controls. The pipe is from
Multipipe, one of the largest manufacturers in the world of multilayer pipes.
Both these companies are well reconised in the industry for the excellence in
product and technical backup. Both Reliance Water Controls and Multipipe offers
full technical support and site visits. Using both these companies, Underfloor
Heating Systems Ltd have created the complete Underfloor Heating System that
provides the customer with the highest quality available to a price that are very close
to a radiator system.
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Introduction
Below we have created a series of answers to a number of design questions we are
frequently asked here at Underfloor Heating Systems Ltd. We hope that these
answers will help you during your project. Any other questions please do not
hesitate to contact our technical department.
• Q) What pipe size shall I use ?
A) Use the 16x2 mm multilayer pipe for the underfloor heating. The Multilayer pipe offers
100 % oxygen diffusion thanks to the aluminium layer.
• Q) How many underfloor Heating Clips should I use ?
A) One clip should be used at every metre of pipe. Note the pipe can also be tied to
mesh on top of the insulation.
• Q) Where do you install Edge insulation.
A) Edge insulation should be installed around all the perimetres of each room. Note
we do not supply the edging strip. This is often installed by the builder. The edge
insulation can be purchased from any builders merchant.
• Q) What is the maximum loop length.
A) The maximum loop length of 100 m must be used in all installations. It is not
advisable to make the loops longer than 100 m. The reason for this is due to the head
pressure from the pump, the pump used is only capable of pressurising water
through 100m of pipe. 100 m of multilayer pipe will cover an area of approximately
25m2. A useful note is to always take the feeder pipes into account from the
manifolds.
7. GUIDELINES FOR THE DESIGN AND INSTALLATION OF
THE UNDERFLOOR HEATING SYSTEM
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A) The pipe is marked every metre. This makes it very easy to check the length of
each loop. When laying the pipe it is important to mark how long each loop is, this
is to allow the flow gauges to be easily adjusted to the right levels.
• Q) How to design the layout ?
A) The pipe pitch (centres) should be 300 mm for new buildings and for existing
properties 200 mm . If one room is for example 15 m2, try to use all the 100m of
pipe, even if it means to use 200 mm centres. The only consequence of using
200mm centres is that the system will respond quicker. The same applies if a room
of a size 22 m2, try to use 100m of pipe, even if it means to use 300 mm centers.
This clearly shows how flexible and cost effective multilayer pipe is when used in an
underfloor heating installation.
• Q) What type if insulation is to be used ?
A) Use 50mm high density insulation below the pipes and 65 - 75mm of screed on
top of the insulation. All installation work must comply with current Building
Regulations. Note the screed drying time can be 4 to 6 weeks before the underfloor
heating system is operated. The mixing valve needs to be set at minimum
temperature when commissioning the system. Increase the temperature by 2 to 3
degrees everyday. This will avoid the screed cracking.
• Q) What are the best types of floor finishes to suite underfloor heating ?
A) Use carpets with less than 1.5 Tog. Any timber floors need to have a moisture
content less than 10 % to avoid shrinkage. If more the timber should be allowed to
dry naturally.
• Q) What are the lengths of each loop.
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A) See instruction in the control pack box.
• Q) How do you lay the pipe ?
A) Always lay the pipe in of heat output importance, for example;
1. Cold spots first. (External walls).
2. Inner walls (Internal wall).
3. Follow the hand sketch or the AutoCad layout provided by us.
• Q) What is the distance between pipe and walls ?
A) The pipe distance from walls should be 100 mm.
• Q) What is the maximum temperature differences ?
A) The system is designed to work with a temperature difference between the flow
and the return. The following temperature differences works well with our system:
5,6,7,8,9 and 10°C.
• Q) What size pump shall I use ?
A) It is recommended to use a pump that can deliver a 60 kPa head. For floor areas
larger than 250 square metre use a 80 kPa head. Note we can supply mixing valves
for both pumps.
• Q) What is the water flow temperature ?
A) The water flow temperature will vary between 35-60°C, depending on the heat
losses from the building. If the system operates with thermostatic mixing valves, use
43°C temperature for screeded floors and 55°C temperature for timber suspended
and floating floors.
• Q) How to Install the Control Pack and the Manifold ?
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A) Maximum heat output from screeded floors is approximately 100 W/m2, the
maximum heat output from timber suspended floor and floating floor is 70 W/m2.
With there being higher standards of insulation in new buildings, average heat
requirements for many buildings are now below 60 W/m2. For small bathrooms it is
standard practice to also install warm water towel rails to give extra heat output as
these areas are usually not very large.
• Q) How does the manifolds work ?
The manifold is supplied with thermostatic option heads on the return and manually
regulated flow gauges on the flow manifold. If individual control is needed,
actuators can be mounted on the return manifold. The flow gauges on the flow
manifold can easily be adjusted by using the key provided and adjusting the nut on
the return manifold before installing the actuators. Normally a 100m loop will have
full flow and half flow will be provided for a 50m loop. The flow rate can be seen
on the return flow meters.
• Q) How do you fill the underfloor heating system ?
A) The system should be filled with water and fully vented of air. This can best be
achieved using mains water pressure through the two end caps on the manifold. All
valves should be closed and the flow end cap connected with a hose to mains water,
with the return end cap connected to a hose laid to waste water point. One by one
flow and return valves are opened and closed on loop purging them of air.
• Q) How is the system tested ?
A) We recommend that your underfloor heating is tested immediately before the
floor is laid. It is recommended to test the underfloor heating system for 24 hours
and using a pressure of 6 bar.
• Q) What is the heat output ?
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A) If required we can supply you with AutoCad design of the underfloor heating
layout. There will be a small charge for the AutoCad drawing. A hand sketch can
be provided free of charge. Please talk to our technical department regarding costs.
Also we can provide a comprehensive site visits if the client feels this is necessary.
• Q) Is multilayer pipe approved ?
A) Multilayer pipe has a full range of European and British approvals, including DVGW,
KIWA and WRC.
• Q) What are the delivery times ?
A) Delivery of all underfloor heating components is normally 3-5 days from
confirmation of your order, subject to availability.
• Q) What is the working life of multilayer pipe ?
A) Multilayer pipe have one of the highest approvals in the world from the Water
Research Council (WRC); 10 bar pressure and 95°C temperature. Even so the
multilayer pipe is guaranteed for 10 years within leaving the manufacturer for any
damages for which the manufacturer can be blamed. When correctly installed,
multilayer pipe will have a working life in excess of 50 years.
• Q) Is there an AutoCad design service and site visit ?
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reserves but because of the environmental pollution caused by inefficient
combustion.
Great strides have been made in the development of new heat source technology
from condensing boilers to heat pumps and these innovations also operate at higher
levels of efficiency when used in conjunction with a heating system requiring only
low temperature water.
Clearly, these factors combine to make hydrothermal floor heating the most
attractive option available today for architects, design engineers and end users.
Standards in home comfort, decor and design have never been higher than at
present. The working environment has also changed, there is even legislation
demanding minimum temperature levels throughout the year.
Many of us now spend as many as 22 out of 24 hours in an artificial environment, at
home, at work or travelling between the two. Making sure that this environment is
as healthy and comfortable as possible has become absolutely critical.
Underfloor Heating Systems Ltd recreated the Roman concept of central heating,
using not warm air generated by furnaces stoked by slaves but low temperature
water circulating in a network of special plastic/metal pipes. The method is slightly
different but the concept is the same, to produce a heating system which becomes
part of the structure of the building and offers comfort that no other system can
duplicate. The kind of comfort, in fact, that only comes from warm floors.
Warm feet and a cool head - that is the kind of real environmental comfort that
Underfloor Heating Systems Ltd is purpose designed to provide. It is invisible and
maintenance free, with no space-consuming, ugly radiators. It requires only low
temperature hot water and is ideal for use with modern condensing boilers. Comfort
levels are high, running costs are low.
8. CONCLUSIONS
In recent times we have been forced to look hard at the ways in which we use up the
energy resources of the planet. Not only because fossil based fuels have limited
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temperatures can actually be reduced by a degree or so and energy consumption in
any well insulated building can be dramatically reduced.
A Underfloor Heating Systems Ltd system has even more to offer - full protection
for safety and long life reliability. Every metre of multilayer pipe carries an aluminium
layer to prevent any oxygen diffusion taking place. Multilayer pipe is 100 % oxygen
diffusion tight. This eliminates any risk of corrosion to metal parts of the system
and means that multilayer pipe can be used in association with radiators in other areas of
the house. It is the peace of mind pipe that is designed to last the life of the building
it serves.
The future of underfloor heating is bright in the UK. The installers and the builders
are starting to understand the value of underfloor heating and the radiator
manufacturers are clearly fighting at the moment to keep their customers.
In Germany for example 90% of the new buildings are installed with underfloor
heating. Scandinavia is also a huge market for underfloor heating. Mostly
underfloor heating in the UK is being installed in houses, factories and leisure
centres. We will soon also see that underfloor heating is being installed in Hotels
and Office buildings, this is a fact in Germany and Scandinavia.
Turning the entire floor area into a giant radiator plane with gentle convection
currents creates the “warm feet, cool head” conditions which research has shown are
ideal for human comfort. Because of this greater comfort effect, design