Electric underfloor heating systems

Unleashing the electric advantage

By Carl Stokes Head of marketing Schlüter-Systems LTD.

THE benefits of locating a heating system under the floor extend from design flexibility all the way through to improvements in health and wellbeing.

In short, the small levy in the initial cost of underfloor heating systems pales into insignificance when considered against the positive long-term impact.

‘Which system should I use?’ is a question posed to Schlüter’s experts on a regular basis. It’s a sensible question, as hydronic and electric systems offer two notably different propositions to specifiers. The answer largely depends on the particular characteristics of your project; here we’ll discuss the technology most often specified through Schlüter-Systems: electric.
The main advantages electric systems offer as a genre are:

Suitability for retrofit
Installation of an electric system is relatively simple and can be performed alongside a routine flooring renovation. Hydronic systems that can be retrofitted are a lot more difficult to find and the process of installation is decidedly more complex.

Zonal heating provision
Where electric systems really come into their own is in the provision of concentrated zonal heating. They are a great choice for infusing additional luxury into particular areas of a project, and enhancing the routines of building occupants.
Examples of this include:

  • Use within bathrooms and wetrooms, to make early morning preparations more pleasant and dry out residual moisture
  • Use around popular communal standing areas in a home, eg surrounding kitchen islands
  • Use in the creation of heated features, eg benches, shelves and walls.

Heat on demand
Electric systems are extremely responsive, taking a short amount of time to heat up owing to their proximity to the surface. The exact amount of time taken will vary slightly, dependent on tile thickness, but they can essentially provide heat on demand.

All electric systems aren’t created equal
In the selection of an underfloor heating solution, deciding on the type of system is only half the battle; the specifier’s next job is to wade through the ever-increasing pool of options available from manufacturers in this marketplace.

A quick web search will give you an indication of the most common format for electric underfloor heating systems: many consist of a roll-out mesh matting with a cable that is taped in place. These mesh systems can be self-adhesive, taped or stuck down via use of a separate adhesive and vary markedly in cost and quality.

The predominance of these systems could trick you into believing they’re the only option for electric underfloor heating. However, there’s another way – one that can save you time, build-up and hassle.

Mesh vs membrane
Electric underfloor heating systems based on an uncoupling membrane first appeared in 2013, with the launch of the innovative Schlüter-DITRA-HEAT-E. These integrated systems offer an enticing alternative to their mesh-based cousins, not least because of their multi-functional nature. In short, they offer a solution that simultaneously heats and protects an installation.

The importance of uncoupling
All materials expand and contract with temperature changes, with tile and stone doing so at a different rate to the substrate upon which they are installed. Direct adhesion of the tile or stone covering to the substrate means the two layers will be rigidly bound together; this inflexible arrangement means movement and stress cracks in the substrate will transfer through to and damage the layer above.

An uncoupling membrane is installed between the substrate and the tile or stone covering, allowing the two layers to move independently and neutralising stresses, meaning an installation stays as perfectly crack-free as the day it was laid.

A key disadvantage of mesh-based systems is they don’t have uncoupling provision, meaning an uncoupling membrane has to be installed as a separate layer. This results in additional installation processes and time, as well as extra height build-up.

For hassle-free electric underfloor heating
The award-winning Schlüter-DITRA-HEAT-E system makes the installation of electric underfloor heating simpler and easier than ever before. Its foundations lie in the market-leading uncoupling membrane Schlüter-DITRA 25, a solution trusted since 1987 to manage movement and ensure tile and stone coverings remain crack-free.

A multifunctional partner
The matting of the DITRA-HEAT-E system offers the same features as its parent product: uncoupling, crack-bridging, vapour management, load distribution and waterproofing.
Additional benefits besides these include:

  • Heating cables that clip securely into the system’s studded uncoupling mat, ensuring even spacing and a consistent heating experience
  • No encapsulation layers required
  • A low assembly height that makes the system ideally suited for most environments
  • Suitability for installation over most substrates

CE Marked waterproofing
The Schlüter-DITRA-HEAT-E system can function as a bonded waterproofing assembly, simply by sealing the matting joints with Schlüter-KERDI-KEBA sealing band and Schlüter-KERDI-COLL sealing adhesive.

The benefits of Schlüter-DITRA-HEAT-E aren’t purely reserved for floors; the system can also be applied to walls. Under-wall heating with Schlüter-DITRA-HEAT-E not only offers CE Marked waterproofing for walls and a great source of heat but is also a safer alternative to a towel rail or radiator, particularly for children and the elderly.

It’s a simple solution that’s very easy to install and allows radiated heating underneath the tile or stone covering, thus keeping the system protected and away from harm.

Reducing layers and height in a heated floor assembly
As the system incorporates uncoupling and underfloor heating, fewer layers are required in the flooring assembly – a traditional system can require numerous products, including insulation board, underfloor heating mat, uncoupling membrane and encapsulation layers, all of which add height to an installation.

By contrast, the Schlüter-DITRA-HEAT-E range can offer solutions starting from just 5.5mm.

The reduction of flooring assembly build-up is a particular concern in the case of renovation projects, where specifiers are working within the predefined limits of an existing structure.

Schlüter-Systems is regularly engaged to provide electric underfloor heating solutions in the renovation of historic buildings, many of which have been standing since the 19th century or earlier.

Integrated thermal breaking and impact sound reduction
Since 2017, the Schlüter-DITRA-HEAT-E system can be specified with Schlüter-DITRA-HEAT-DUO matting, which boasts the additional features of an integrated thermal break and impact sound reduction of up to 13dB.

These two additional features are achieved thanks to a unique 2mm fleece layer on the underside of the uncoupling membrane, which allows 80% of the heat to be pushed to the surface during the heat-up phase for up to 70% faster response time, as well as reducing impact sound by a perceived 50%.

A thermal break is an element within an assembly which reduces the flow of thermal energy between conductive materials. The thermal break in Schlüter-DITRA-HEAT-DUO ensures the heat doesn’t get lost, but is instead transferred directly to the floorcovering above.

This unique combination of fleece and matting allows an input of 136 W/sq m, to push up to 110 W/sq m to the surface, reacting faster than 200 W/sq m systems and making Schlüter-DITRA-HEAT-E-DUO cost less to run compared to other systems, which lose 50% of their heat into the subfloor below.

The Schlüter-DITRA-HEAT-E-DUO system comes in at a total height of just 7.5mm. The introduction of this solution means even thinner floor assemblies can be specified, as the additional features negate the need for a separate soundproofing layer.

Looking for hydronic underfloor heating instead?
Schlüter has a solution for this as well. The Schlüter-BEKOTEC-THERM system takes an integrated approach to the installation of hydronic underfloor heating, providing solutions to many of the problems associated with traditional underfloor heating installations.

The system offers many advantages to both the specifier and installer, including removing the need for screed movement joints, which allows for more control over the design of the surface covering. The considerably lower installation height of the Schlüter-BEKOTEC-THERM underfloor heating system, coupled with the unique design of the Schlüter-BEKOTEC modular screed panel, means less screed is needed – making it easier, quicker and cheaper to install and run.

Learn more about specifying underfloor heating
Specifiers can learn more about how to successfully select the underfloor heating systems that best suit their projects in the CPD seminar ‘Specifying Integrated Underfloor Heating Systems’. This CPD seminar focuses on the modern advances made in this popular arena, discussing hydronic and electric technologies and their capabilities.

It’s delivered in the form of a 45-60 minute presentation, held at your offices and your convenience.

To book a CPD Seminar, call 01530 813396, training@schluter.co.uk or visit www.trainedwithschluter.co.uk.

Schlüter-Systems has dedicated consultants on hand to help with any stage of your specification project.

NBS Clauses and BIM Objects for Schlüter-Systems are available on NBS Plus, National BIM Library and at www.schluter.co.uk.

Schlüter-Systems Ltd
01530 813396