The first electric heating cable with guaranteed reliability

When installing electric underfloor heating, you hope never to go back. ThermoSphere Ultimate® is quick and easy to install, plus it’s the most reliable underfloor heating cable on the market. That’s because ThermoSphere Ultimate combines a TwistedTwin cable, and in-line joint technology. This removes the risk of damaging the cable during installation, as cutting into the membrane and substrate is no longer required.

When you need reliability, fit ThermoSphere Ultimate. You’ll never go back.

Flooring Innovation Awards_Gold Winner 2023_ThermoSphere Ultimate



For total peace of mind

With guaranteed reliability there's little to no chance of the cable failing when installed correctly. We’re so confident about this that should the underfloor heating system fail in the first twelve months of installation because of a manufacturing fault, we will not only replace the system, we'll also replace the floor covering too.* So, sit back and relax because we’ve got you covered.
*Available after confirmation of successful warranty registration. 

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ThermoSphere Ultimate Heating Cable Comparison

Speed up installation and reduce risk

Unlike most electric heating cables, there's no bulky hot/cold joint that needs cutting into the floor. This transforms installation into a one-step process, making it faster and easier while significantly reducing any chance of accidently damaging the cold tail joint during installation. No cutting also means the membrane’s waterproofing layer stays intact.

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Ultimate System Installation

Use it with any decoupling membrane mat

ThermoSphere Ultimate is compatible with all decoupling membrane mats. This means you can use your preferred brand of decoupling mat with the easiest to install and most reliable heating cable.


Installation guide (PDF)

ThermoSphere Ultimate with any heating and decoupling membrane mat

Take advantage of in-line joint and TwistedTwin technology

ThermoSphere Ultimate is the ONLY heating cable to combine in-line joint technology with TwistedTwin cable construction. This makes it the most robust 'in-line joint' heating cable you can use – giving quick quality workmanship for your customers.

Download the data sheet (PDF)

Ultimate System

A cable for every project

We've introduced four new cable sizes into the ThermoSphere Ultimate range. You can choose from a wider range of cable sizes: 42m, 55m, 90m and 175m. These new sizes give installers more options to ensure they can install the perfect heated area without needing to use multiple cables. 


Cable size options

ThermoSphere Ultimate Heating Cable Reel

Installers: 5 Reasons to choose NEW first-of-its-kind in-line joint and TwistedTwin heating cable from ThermoSphere

Our new ThermoSphere Ultimate heating cable brings many benefits to installers and homeowners. With a cable for every project, find out how it can help make installation quicker, easier and give a quality finish for your customers.

Read the blog

Tilling over Ultimate system

Ask the expert

We’ve been driving innovation in electrical heating for over 25 years and our first-of-its-kind ThermoSphere Ultimate heating cable was designed to enable installers to complete projects hassle free and deliver quality workmanship. We spoke to our design team about the technology behind the cable and how it can prevent faults while speeding up installation.


Hear from our expert

ThermoSphere Training & Development


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Your ThermoSphere Ultimate® questions answered

We know that some questions are more complex than others, so our team is always available to help.


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