A frequently asked question is whether it is possible to retrofit underfloor heating to an existing floor. The terms ‘refit’ and ‘retrofit’ get often confused and in most cases people mean retrofitting. We are here to bring clarity to the suitability of underfloor heating with either type of home improvement, refitting and retrofitting, and to answer all questions you may have in regards with them.

To start with Warmup underfloor heating can be fitted both into new-build and older properties and nearly all electrical underfloor heating systems can be fitted onto existing subfloors.

Foil Heater


First of all, let’s begin with a definition – retrofitting.Retrofitting means the process of adding components to already existing projects. In this context we mean installing underfloor heating onto existing floors when renovating a room or a house. Electric underfloor heating is well-suited to retrofit projects. In this section we are going to answer the questions:

  • Does installing underfloor heating raise the floor levels?

  • Why is electric underfloor heating the best retrofit option?

As mentioned earlier electric underfloor heating can be fitted in both new and old properties, and on existing subfloors. However the actual floor finish such as tile, laminate or vinyl needs to be removed and replaced with a new floor finish. In other words, fitting underfloor heating onto existing floors means removing the existing floor covering, adding insulation boards (if necessary), installing the heater on them and then laying down a new floor covering above the heating system. It is very difficult to lift up the existing floor finish and lay the same floor back again after the installation of an underfloor heating system. It goes without saying that most of the floor finishes such as tiles are doomed to get damaged when lifting the floor up. Electric underfloor heating is therefore a perfect option for people who are wishing to change their floors whilst renovating, because the heater is very thin and does not raise the floor height visibly.

The installation of the electric underfloor heating system is also quick, easy and clean. However it is important to involve a qualified Part P certified electrician in the project to ensure that the electrical distribution is designed and carried out correctly.

Retrofitting of other heating systems usually means more laborious work including removal of old floors (not just the floor finish but the whole floor), refitting of new ones and finally, installation of pipework and boilers. This again increases the overall cost of the renovation.

Underfloor heating


As discussed earlier many people confuse the terms ‘refit’ and ‘retrofit’. For those ones who nevertheless are looking to actually refit the system, we must say that an electric underfloor heating system should only be fitted once. It is not possible to take up an existing system and refit it into a different room. This is due to a number of issues:

The wires can be damaged when removing the floor finish, specifically tiles or stone:

  • The wires can be damaged when removing them from the adhesive, especially if they are pulled, stretched or bent.

  • If the wire is on a mesh, it may prove impossible to remove the system without damaging it, as the mesh should be fully embedded in the adhesive.

  • A heater can only be used in the room size it is designed for, therefore refitting an existing installed heater into another room would not work.

It is also good to bear in mind that to refit a heating systems would void any guarantee or warranty.


The ease of fitting an electric underfloor heating systems has allowed millions of homeowners to install a warm, comfortable and highly controllable heating in individual rooms or as a whole house heating systems.

Underfloor heating can be controlled with any thermostat. The increase in technology in thermostatic control systems has allowed the heating systems to work automatically without you needing to manually control them. The Warmup 4iE Smart WiFi Thermostat learns your habits, knows when you are in and can even predict when you are coming back home, adjusting the temperature accordingly. With the MyHeating app to go with the thermostat you can control the heating in your home from a remote location. A smart thermostat does not only increase the overall comfort, but decreases energy usage, as your heating is on for less time and only when you need it, leading to cost savings.

In many cases the floor can be powered using existing ring mains with a fused spur powering the thermostat. All heating systems should always be powered by a circuit protected by a Residual Current Device (RCD). If any of these terms sound unfamiliar It is recommended to consult with a qualified Part P certified electrician in regards with RCD.

Underfloor heating - warmup


There is a wide range of underfloor systems available for different floor coverings as well as subfloor types including concrete, stone, and engineered woods. For all floor types, it is advisable to ensure adequate subfloor insulation when considering retrofitting an underfloor heating system. Subfloor insulation can be installed effortlessly using Warmup Insulation Boards (WIBs). These boards have excellent insulation qualities. The range includes insulation boards for different needs of insulation. If concerned about the floor heights, the Warmup insulation board for concrete floors is only 10mm thick and for wooden floors 6mm thick. Although insulation is not a prerequisite, it is recommended to ensure heat is directed upwards and not into the subfloor. Good insulation decreases the heat up time and ensures the system is as efficient as possible.

When tiling or laying stone floors, it is always important to ensure the floor is sturdy and free from flexing, regardless of installation of an underfloor heating system. If in doubt, the floor might require additional strengthening of a quality plywood or other appropriate material.

Finally, electric underfloor heating does not require any maintenance unlike conventional heating systems ran by boilers. Therefore it is a secure and cost-efficient heating system that lasts for a lifetime whilst keeping your toes warm and cosy. Call the Warmup Technical helpline on 0345 345 2288 for further advice or send a quick quote to inquire prices for your project.


Underfloor Heating

Underfloor Heating from the Worlds Best selling Brand, Warmup, starts from less than £200 and costs less than £20 per year to heat a typical bathroom floor – all with a lifetime warranty”.

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