2 min read

The Do’s & Don’ts of electric underfloor heating installation

The Do’s & Don’ts of electric underfloor heating installation

We’ve pulled together some of the most important points to remember when installing electric underfloor heating. But please remember to contact us should you have any questions before, during or after the installation.


Measure up properly. If there is too much matting or heating cable and you have not cut or damaged it, you can simply exchange it for the correct size heating system, but remember re-seller returns policies can differ.

Make sure that you keep at least 50mm of space between each run of heating cable and ensure the cables do not touch or cross over.

Check with your flooring manufacturer for compatibility of your chosen floor finish with electric underfloor heating.

Ensure all heating cables and cold tail connections are fully embedded within a layer of flexible tile adhesive. Failure to do so will cause the system to fail over time and can present a fire hazard.

Make sure that electrical work is carried out and tested by a qualified electrical professional.

Complete your online warranty registration within 60 days of purchasing your chosen electric underfloor heating solution.

We don’t mean to state the obvious but DO remember to read all installation guides before commencing installation of your electric underfloor heating system!


Don’t ever cut or shorten the heating cable! Every ThermoSphere electric underfloor heating mat and cable is designed to a specific resistance rating – this is what creates the heat. If the heating cable is cut or lengthened, that resistance rating changes and the cable can become damaged, or not heat up sufficiently.

Don’t place the cold tail connection or end termination in a recess in the floor/insulation boards and then cover with tape. This causes an air pocket and can lead to cable failure.

Don’t hide coils of unused heating cable under fixtures such as baths and kitchen units (believe it or not we have seen this before!) If a system like this is connected to the electricity and switched on it will simply fail.

Don’t position temperature sensors near heat influences such as heating/water pipes or large glazed elevations.

Don’t turn on the system until it is fully installed and all adhesives, levellers and grouts are fully cured – usually 7-14 days. You don’t need power to test the system!

Don’t directly cover a working underfloor heating system. Air must be allowed to circulate over the floor. Any permanent furniture must be on bun feet or similar.

Don’t attempt to carry out any electrical work if you are not a fully qualified electrician.

Don’t hesitate to contact us if you have any questions during installation our technical team are here to help! Give them a call on 0800 019 5899.


Got any questions about electric underfloor heating?

Send us a message

best underfloor heating for vinyl floors

4 min read

Best Underfloor Heating for Vinyl

‘What’s the best underfloor heating for vinyl floors?’ is not an uncommon question we get asked. Vinyl flooring is becoming a more popular floor...

Read More
Bathroom Design Trends for 2023

4 min read

Bathroom Design Trends for 2023

It’s that time of the year where we take an honest look at bathroom design trends for 2023. So, we’ve scoured the internet, read through a heap of...

Read More
The disadvantages of electric heating

4 min read

What are the disadvantages of electric heating?

The energy crisis and extreme price volatility in fossil fuel markets has had a dramatic impact on the cost of living for many homeowners, and as a...

Read More