About Underfloor Heating…

Underfloor Heating is the latest modern idea to heat your home or workplace. Electric Underfloor Heating and Warm Water Underfloor Heating are cost effective ways to heat any room because they heat the lower part of the room first – instead of the ceiling.

Component Parts of Underfloor Heating Kits

Depending on the Underfloor Heating Pack you buy – it will be made up of certain component parts. These parts may include:

  • Underfloor Heating Pipe
  • Underfloor Heating Insulation
  • Underfloor Heating Mats
  • Underfloor Heating Manifolds
  • Underfloor Heating Thermostats

Underfloor heating can be purchased specifically for the following applications:

  • Timber Floor Underfloor Heating
  • Concrete Floor Underfloor Heating
  • Under Tile Underfloor Heating
  • Inscreed Underfloor Heating
  • Under Carpet Underfloor Heating
  • Loose Laid Cable Underfloor Heating

What is Underfloor Heating?

Under floor heating is a form of central heating which utilizes heat conduction and radiant heat for indoor climate control, rather than forced air heating which relies on convection. Underfloor Heating Heat can be provided by circulating heated water or by electric cable, mesh, or film heaters.

Under floor heating can be used with concrete and wooden floors, with all types of floor covering (e.g., stone, tile, wood, vinyl, and carpet), and at ground level or upstairs. Choice of floor finishing requires careful consideration, because changes of floor finish may affect performance.

What are the advantages of Underfloor Heating

Under Floor Heating has an improved thermal comfort…
Radiant heating is arguably superior to convection methods because warm, buoyant air rises wastefully to the ceiling in convection-heated rooms, warming the upper body (often with some discomfort, particularly to the head) but leaving the lower body cooler.

In contrast, in-floor radiant heating warms the lower part of both the room and the body because when warm air convects from the radiant floor surface, it loses approximately two degrees Celsius at two meters above the floor. This imparts a feeling of natural warmth, since the limbs should ideally be warmer than the head. (The most acceptable indoor climate is one in which the floor temperature ranges between 19 and 29 °C and the air temperature at head level ranges between 20 and 24 °C.)

Humidification may still be needed for thermal comfort with a radiant system, but, for a given relative humidity, likely less humidification is needed than for forced-air heating. This is because forced-air systems, when improperly balanced (e.g., because of leaky ducts), can draw in outside air which typically has low moisture content in the winter. [1] Asthma sufferers may benefit from underfloor heating because it reduces the airborne circulation of both dust and dust mites.

Under Floor Heating is more Aesthetically Pleasing
Underfloor heating is invisible from above and does not use valuable wall space with unsightly heating equipment. In a sense, the entire floor is a radiator, although, because of its area, it need not reach the high temperatures of a steam radiator. It has a particular advantage in public areas where exposed hot or sharp surfaces can be dangerous and unsightly.

Underfloor Heating gives greater Energy efficiency
Air-infiltration heat loss is reduced significantly compared to forced-air systems in which imbalance due to duct leakage can drive infiltration of outside air into the building. Heating cold air from the outside requires extra energy and decreases humidity, as discussed above.

If the boiler water temperature in a hydronic system is set to the relatively low temperature required by underfloor heat, rather than the higher temperature typically used in other types of radiators, the boiler may have higher efficiency and lower standby losses. However, this is typically only possible in a boiler designed for condensing operation; in many boilers, the water temperature in the boiler must be set higher, and reduced by a mixing valve. Depending on the piping layout and insulation, there may also be lower heat losses in the water distribution system because of the lower temperature.

Although electric underfloor heating can deliver almost 100% of the electric energy coming into the building to the heated space, overall system efficiency of electric heating is low because generating electricity from heat is less efficient than using the heat directly.

The Cost of Under Floor Heating

Although it can be more expensive to install than radiators (it can be comparable due to the increasingly competitive market), wet underfloor heating often proves more economical in the long run, particularly in well-insulated larger properties. Energy savings of up to 40% can be achieved compared to conventional heating systems if a condensing boiler is installed, but even with a standard boiler up to 15% energy savings are normal. The efficiency of condensing boilers is enhanced thanks to water returning at a lower temperature.

By employing full lengths of piping without any joints, wet underfloor heating loops are practically maintenance free. The piping used can have a lifespan of up to 100 years. Reliable materials are critical because repair is difficult. The central heating equipment, pumps, and controls, like others, requires periodic maintenance and replacement.

The Wet Underfloor Heating System

In a Warm Water Underfloor Heating System – Hot Water is circulated through pipes or tubes that are laid into the floor (usually a solid-screeded floor, although joist-based systems also work well). Various types of pipe are used including PEX, multi-layer (a composite of PEX, Aluminium and PEX) which is also known as Alupex (there is also a version using PERT instead of the PEX) and polybutylene (PB): copper pipes are not normally used.

Gas Boilers, Oil Boilers, Solid Fuel Boilers or Electric Boilers can be used as the source of heat for any underfloor heating system, as can a number of other technologies. Condensing boilers and ground-coupled heat pumps are particularly well-suited as the operation of underfloor heating systems allows them to operate in their most efficient manner. Underfloor heating can run as low a temperature as 35 °C (95 °F), allowing a heat pump to run at a coefficient of performance in excess of 4.0, compared to the 3.0 with the temperatures needed for use with wall radiators.

Wet underfloor heating systems can also be used in reverse, where cold water from a chiller is placed in the system taking heat energy out of the building. However, care is needed to ensure that surfaces’ temperatures remain above the air’s dew point temperature. Otherwise, slipping hazards or mold growth are a concern.

Electric Under Floor Heating systems

Electric Underfloor heating systems have very low installation cost for smaller spaces (1-5 rooms) because they are easy to install and have a very low start-up cost.

Another advantage of electric underfloor heating over a warm-water system is the floor build up/height. Floor build up can be as little as 1mm. The electric cables are usually installed onto an insulation board or directly onto the subfloor or padding (under carpet or laminate); then the floor covering is placed directly over the heating system or thinset.

Electric underfloor heating also benefits from faster installation times, with a typical installation only taking half day to a day depending on size to install. Also warm up times are generally a lot quicker than “wet” systems because the cables are installed directly below the finished flooring making it a direct acting heat source rather than a storage heater.

The Electric Underfloor heating system used to be supplied as one long continuous length of cable with the consumer having to weave the cable up and down the floor at a pre-determined spacing and making a return loop to complete the circuit. The main problem with this was that the installation was time consuming, and also the risk of hot and cold spots due to uneven cable spacing; the closer together the cable the more heat was given off, and visa versa. With today’s technology most modern cables have a built in return, meaning that you only have one end to connect instead of having to bring the end of the cable back to the start to make a full circuit. These are excellent and make the installation a lot easier. With the introduction of the built in return came the cable mat. These have revolutionised the electric underfloor heating market due to the simplicity of the installation. Cable mats have taken the hard work out of the installation by having the heating cable already pre-spaced on to a nylon mesh. All you have to do is simply start at your thermostat location and roll it out over the floor until it’s all used up. These save time and offer less risk of having hot and cold spots.

One technique is to lay the heating cable directly onto an insulated concrete floor and then apply tile on top of it. Where time-of-use electricity metering is available, this type of system can be turned on at night when electricity rates are low, and then allowed to warm the house during the day by relying on the heat energy held within the thermal mass of the concrete.

Sometimes, in order to mimimize floor buildup, a screen or carbon film heating element is used. These systems are generally used under laminate or similar types of flooring..