Underfloor heating

The warm up time of a heating system will be dictated by the insulation used beneath it and the output of the system. In general, the better insulated the sub-floor the faster the system will warm up, with Marmox Thermal Tilebacker Boards offering a very speedy warm up time, and un-insulated concrete offering the slowest warm up time. Using a 200W system beneath ceramic/stone tiles provides a faster warm up time than 150W or 160W systems. We recommend using Marmox Thermal Tilebacker Boards wherever practical when installing our systems onto concrete floors.

The cost of running a system is based around many different factors so it is hard to generalise. When our systems are used in well insulated buildings, for instance insulated up to the current building regulations, and they are used with our CPS thermostat correctly set, the cost per square metre of heated area would typically be between £2.80 and £4.10 per annum. When used to heat a conservatory the system could typically cost up to £7.00 per square metre per annum to run with a reasonably well insulated floor. This should be more efficient than any other form of electric heating and will often be cheaper than a radiator system.

The truth is very simple, with any mains voltage electric heating system one kilowatt of electricity will produce one kilowatt of heat, whether it is a 3mm or 7mm cable, heating mats or heating ribbons. With a low voltage system there is a small amount of wasted energy in the form of heat and noise within the transformer. The only things which significantly affect the cost of running one system compared to another are the insulation used beneath the system, the output of the system and the use of an intelligent thermostat. In general, the better the insulation used beneath it, and the higher output of the system, the cheaper it will be to run as long as it is used with an intelligent thermostat like Heat Mat’s CPS thermostat/timer.

Unlike CE marking, which is a non-independent self-certificate, BEAB and VDE system approvals are completely independent. A system approval, such as Heat Mat have on their heating mats, means that BEAB and VDE have independently verified and tested the heating mats with Heat Mat’s thermostats and they have confirmed that the system is safe and suitable for use as underfloor heating and that it complies with all necessary legislation. At the time of writing Heat Mat are the only manufacturer with this approval, and all of our heating mats, cables and thermostats are manufactured in BEAB approved factories.

If the system is used with the thermostats adaptive function switched on then the 200W system will be slightly cheaper to use than the 150W system. This is due to the warm up time of the 200W system being slightly faster.

If you have installed your heating beneath tile adhesive, levelling compound or a screed you must allow this to dry out before turning on your system for the first time. If the system is turned on too early it will force the moisture out of the covering which may lead it to crack. We would recommend speaking to the manufacturer of your flexible tile adhesive, grout or screed to confirm the drying time required.

Are the heating systems connected in parallel or series?

If your chosen system exceeds the maximum Amp rating of your thermostat, you should consult your electrician who will be able to advise you on using a contactor to control the system.

We would recommend that each room has its own heating system controlled by its own thermostat. This will allow for simpler and more accurate temperature control of each room and will avoid heating rooms which do not require it.

The heating cable/ribbon cannot be shortened because each heating element has an adaptive resistance suitable for only one length of cable. If you shorten the cable it will not operate correctly.

If you install 150W heating mats beneath a levelling compound, or 7mm cable at 160W/m² beneath a screed virtually any floor covering can be laid on top.

You can tile straight onto heating mats and 3mm cables as long as you use a flexible tile adhesive and ensure that all of the heating cables are thoroughly covered. If installing a system in this way the tiler should take particular care not to damage the heating cable when cleaning out grout lines.

Although the heating systems are very robust, accidents do happen! Luckily, it is very simple to repair all of our heating elements if the damage is found before they are covered. If a heating element is damaged please contact your supplier to arrange for a repair kit and easy to follow instructions to be sent to you.

In the very rare occasion that a system stops working once it has been covered all is not lost. Usually the problem is related to the electrical wiring or thermostat connections and if you speak to Heat Mat’s Technical Team they should be able to assist you in locating and correcting the error. If the fault appears to be located beneath a tiled floor or levelling compound, Heat Mat can provide the services of an independent engineer who specialises in locating and repairing damaged heating systems. The damaged area is located by using a thermal imaging camera and usually can be pinpointed to an area roughly the size of a ten pence piece. The engineer can then repair the cable beneath the floor by removing the minimum amount of tiles or compound. There is a charge for this service if the damage is found to have been caused subsequent to Heat Mat supplying the product.