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Design

All of our designs are fully compliant with BS EN 1264 & BS 8204

Designs are backed by full design indemnity insurance, up to £1,000,000.00

Floor structures

Underfloor heating & cooling can be installed into solid concrete, timber suspended or floating floor structures with virtually no limitation or adverse affects upon the wide range of surface finishes currently in use.

For specific floor structures click on underfloor heating tab (top menu).

How does underfloor heating work?

Radiators heat the air in the room by convection, drawing cold air across the floor and sending it up to the ceiling. In contrast, underfloor heating warms the lower part of the room where the occupants are, with the feet just slightly warmer than the head. A high proportion of the heat emitted by an underfloor heating system is radiant. The occupants are heated directly; the air in between less so.

By passing a regulated flow of pre warmed or pre cooled water through embedded pipework true radiant heating or cooling can be achieved to great effect.

 

Brief details below or follow the link for full heat loss and UFH calculations

In order to design a system we must first calculate the heat losses as for any heating system (we can disregard downward losses for the moment they are added later for total loading and boiler sizing). If a room has very high ceilings then only take into account the first 2.4m (providing there is a roof or ceiling). The heat loss is then divided by the useable floor area (that means floor not taken up by units, baths, showers or other permanent fixtures).
This gives us Watts per meter squared. For a screed floor the maximum load is 100 watts per meter squared (70 watts for a timber construction).
If the calculated watts per m2 are less than this, underfloor heating is suitable for that room or area.
This will help you to determine for yourself the suitability of underfloor heating for a particular project however the gauging of the pipework centres is more complicated and can be discussed in detail with members of our design team.

Consultants please follow the link to carry out full heat loss/ UFH calculations and receive a quotation for your project.    

 

Important aspects of underfloor heating design

PIPE SPACING
  • Pipe centres, these must be sufficiently close so as to avoid hot and cold banding across the floor. Generally 150mm – 300mm. Closer pipe centres at a given temperature and flow rate will emit more heat energy.

FLOW TEMPERATURE AND RATE OF FLOW

  • Flow rate and temperature. Calculated to give the optimum out put of heat energy (or absorption in the case of underfloor cooling) to reach the room set point temperature, taking into account the amount of heat loss in that area.

INSULATION

  • Insulation is required in all underfloor heating applications for the following reasons:
    • Reduction of downward heat loss – To conform with current building regulations
    • Pipe fixing platform for underfloor heating pipework.
    • Compressive support for screeded and some floating floors.
    • The insulation density ((kPa-Kilopascals) (1000 Newtons per M2 )) is also crucial in screed floor applications to avoid the floor being damaged through compression 70-100kPa is the minimum we would recommend with upper limits as high as 500 kPa.
  • EPS Expanded Polystyrene. 70, 100 or 150KPa–, commonly used in UFH applications. Cost effective and readily available. R Values from 0.038 W/mK upwards and compressive strengths of 70KPa – 150KPa are typical.
  • Sheets are available in a range of sizes and thickness’s and may be ordered with pre routed pipe channels, pre laminated membrane or plain.
  • XPS- Extruded Polystyrene. 200 – 500KPa. Generally more expensive but with much improved thermal and compressive qualities. Prices and specifications can vary greatly with different brands.
  • Sheets are available in a range of sizes and thickness’s and may be ordered with pre routed pipe channels or plain.

 

CONTROL

  • Zone control: Part L,2 of the building regulations state that “Any area greater than 150m2 must have a full- time, temperature and flow control. Correct zone control is critical in ensuring that the system is working at its most efficient.
  • Choice of controls: HS Tech offer a wide range of controls to suit every type of project. Our control range includes features such as:
    • Weather Compensated systems.
    • Low voltage systems.
    • Wireless Controls.
    • Heating/Cooling. Automatic changeover.
    • Fully automated heat up and cool down sequence modes.
    • Proportional Intelligent Systems - learn the heat up trends of individual areas to give optimum performance. These systems help eliminate energy under and over shoots and thus reduce running costs significantly.

Usable Applications

Underfloor heating and indeed cooling can be installed installed into solid concrete, timber suspended or floating floor with virtually no limitation or adverse affects upon the wide range of surface finishes currently in use.

Special application – Plate diffusion systems

Whilst heat will transfer through wood (or low thermal masses) quite quickly it will not spread out as it would through screed (or high thermal masses) and so the banding effect will be much more pronounced. To counter this we use diffuser or conductor plates which spread the heat from the pipe and warm the whole floor. Start up and cool down times are very quick with these types of system. Radiators heat the air in the room by convection, drawing cold air across the floor and sending it up to the ceiling. In contrast, underfloor heating warms the lower part of the room where the occupants are, matching closely the ideal heat comfort profile, with the feet just slightly warmer than the head. A high proportion of the heat emitted by an underfloor heating system is radiant. The occupants are heated directly; the air in between less so.

Whilst heat will transfer through wood (or low thermal masses) quite quickly it will not spread out as it would through screed (or high thermal masses) and so the banding effect will be much more pronounced. To counter this we use diffuser or conductor plates which spread the heat from the pipe and warm the whole floor. Start up and cool down times are very quick with these types of system.