Electric Underfloor Heating
Electric underfloor heating has been in use throughout Europe for several years. It is now being more widely used in the UK as it offers better energy efficiency and versatility of installation, making it an excellent choice for renovation projects.
The system consists of a series of electrically resistant cables which are laid into new flooring, or beneath existing flooring.
Installation of Electric Cables for Underfloor Heating
The cables can be ribbon type cables, or can be woven into mesh matting, either of which can be cut to suit the layout and size of the room.
How does it work?
The circuits of the system are all connected to the mains supply individually via their own circuit breaker. Running a current through the circuits causes the cable or mat to heat under resistance and this heat is transferred into the flooring and then radiated into the room.
This creates a large surface area which enables a slow and even release of heat. The radiant effect of underfloor heating, as opposed to convection heating, means that heat is absorbed into the furnishings and objects in the room.
Each of these objects then emits heat in its own right, providing more even distribution throughout the room.
Electric underfloor systems are a direct heat source, as they heat the concrete or timber of the floor directly; rather than an indirect ‘wet’ system, which heats through its pipe work.
This gives electric systems an advantage as they have a quicker initial heat up time than wet systems.
Where can it be installed?
Electric underfloor heating is very versatile in terms of installation. It can be incorporated into a building design much like any other system, and the cable fitted during construction.
This affords all the flexibility of other heating systems, whereby different rooms can be heated individually at different times and to varying temperatures.
It is most prominent in refurbishments however, as it can be retrofitted very easily and inexpensively.
While a wet system may require floors to be dug up and plumbing alterations, an electric system can be fitted by almost anyone; the only requirement is that a qualified electrician makes the connections to the mains supply.
It requires much less depth than a wet system, the typical profile of the cable or matting is 3mm, so it is much easier to install into existing buildings without having to raise the floor level too much.
This prevents the need to alter skirting and doors within the property, and is an important consideration in buildings which already have low ceilings, or limited space.
It can be installed underneath almost any type of floor, laminate, carpet, or tiled floors. The cables or mats are laid on the existing sub-floor or insulation board, and the flooring re-laid on top.
Some of the cheaper systems, however, may not be suitable for manufactured laminate flooring due to the heat.
Ribbon cabling, which can operate as low as 30°C may be the best option with that kind of floor to avoid damage to the colour or finish.
If you are intending only to heat one room, single mats can be bought and cut to size to suit the installation. This is a very cheap and effective way of introducing new heating into a previously cold room.
What are the costs?
The cost of installation will depend on the size of the area to be fitted with underfloor heating, and whether it is a retrofit or a new build.
In general, however, electric underfloor heating is less expensive than water based systems, or conventional heating systems.
The price checker website, Checkyourprice.co.uk, estimates the cost of installation at a cost of £15 per square metre for the installation of the heating system, and £180 per zone for the connection and testing of the electric supply.
The cost of the system itself will vary with the type of cable or matting used, and the type of timers and control units included.
As a rough guide, prices from Handy Heat, range from £125+VAT for a 1m² cable mat, to £642+VAT for 20m² of matting. The mats can produce 150 watts per square metre and are recommended for timber and concrete sub-floors.
Installing Wiring for Electric Underfloor Heating
Matting which can produce 200 watts per square metre, and is recommended for conservatories retails at £393+ VAT for 10m². While 15 metres of cable which will cover approx 1.25m² and can produce 150 watts per square metre, comes in at £120 for the kit.
Running costs of the system is difficult to gauge as different people will use their heating differently, but Floor Heating Online give an interesting example of typical running costs based on heating a concrete floor with an area of 10.63-12.80m², using a 1700 watt cable.
Their figure of £214.76 per annum is based on a cost 8p per KWh and the heating being on for 18% of the time during the year.
What are the disadvantages?
One problem that many people find with underfloor heating is that the initial heat up time is longer than they had expected.
Although electric underfloor heating has a quicker heat up time than water based systems, this is still something to consider, particularly if you are installing it into a conservatory where the room may get very cold and will not heat quickly on demand.
For very large rooms and properties, it may be difficult to find a system that is suitable. Underfloor heating systems can only provide a certain amount of heat, and may need to be used in conjunction with radiators to completely heat the building.
The running costs do tend to be more expensive than those of water based systems, so in the long term will not represent the same level of savings.
It is worth remembering that this may be offset by the cost of initial installation, as electric systems are generally cheaper to fit initially.
Mats and cables are versatile as they can be cut to suit the layout of a room, and can be fitted to avoid any permanent fixtures and fittings. This can present a problem in the future, however, if you decide to change the layout or re-decorate the room.
Summary
Electric underfloor heating is a cheap, flexible and effective form of heating. It is more energy efficient than conventional heating systems, providing an even temperature throughout a room from floor to ceiling.
It is cheaper to install than water based systems, and can be retrofitted very easily. Cabling and matting supplied for the purpose can even be cut to suit the shape and layout of your rooms.
The systems come with all the functionality you would expect from a modern heating system, and can be timed or set to maintain different temperatures in different rooms.
While it may not be the right decision for every property, electric underfloor heating is one option that should be given full consideration if you are installing a new heating system.
