Underfloor heating review, which is good or bad? how do you tell?
Underfloor heating reviews are few and far between. We put this question to Richard Bevan the CEO of DK Heating Limited. Richard has been involved in heating quality assurance for many years and is a well respected figure in the underfloor heating industry.
High quality underfloor heating comparisons with cheap imported products:
These are the thoughts and concerns when it comes to comparisons between high quality electric underfloor heating products and some poor quality imports. All these points are based on tests conducted at our test laboratory and were discussed at the IEC 60335-2 technical committee of which I am a member.
The underfloor heating wire is made up of the following parts:
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Heating conductor
As you know the heating conductor are manufactured by bunching several strands of heating alloy together to give the correct resistive circuit and ohms per meter. When designing a heating wire there are several key points to adhere to. However one is extremely important and that is to ensure that when bunching the strands together they should all be the same material and size. When we test some products they all have differing materials in each strand and have different size strands. For example we would use 7 strands for our heating wire designs. We would use 7 strands of pure copper and each strand would be 0.1mm in diameter. We use an odd number of strands so we get even wire diameter with a centre strands and six strands on the outer. A cheap design would have an even number of strands, making an uneven finish. The strands normally vary in diameter and material making for a design that will work initially but will ultimately fail. Having differing materials in a stranded bunch means that you get a disparity during expansion and contraction which will lead to failure of one or more strands causing the unit to get hotter and eventually fail.
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Earth Braiding:
Typically cheaper wires will have a bare braid i.e. bare copper which will work fine initially. Lets remember that we are burying this cable in cementitious material and so there is a chance that the earth braid may have moisture ingression and in such instances copper will corrode and give a ground/earth fault. Our braid material is a tin plated copper or stainless steel offering better protection against moisture ingression and premature earth faults.
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Insulation materials:
Our products are extruded with Tefzel ETFE which is an extremely strong material. Poor quality companies use inferior grades or even engineered polymers as alternatives. There are a number of reasons but primarily ETFE is only produced by 3 companies worldwide and pricing is influenced by this. Therefore availability and pricing can be issues. The insulation materials are tested to ensure that after 10 years operating they retain 75% of the tensile and elongation properties and maintain their electrical strength. These tests are conducted by age testing the product. In tests where cheap comparisons have been used these products fail after what is effectively one year operating. They may well offer a 25 year or lifetime warranty but they are really hoping that a consumer will not follow up on the warranty.
Typically a cheap product can look ok when purchased and will work ok when installed. However, after a period of time, depending on how often it’s used the product can fail prematurely for one or all of the reasons above. If someone has been selling these products I would expect them to see a rise in warranty calls after 1 to 2 years. This can prove to be quite an expensive activity and I wouldn’t bank on a warranty call from a cheap supplier.
If anyone would like to contact Richard to discuss this please contact us and we’ll forward your details.