Calculate your electric heating

To help you calculate your electric heating sizes, we’ve created a handy online calculator to guide you in your decision on which products to purchase.

You’ll also find a range of tools, resources and information so you can calculate the necessary radiator elements, towel rail requirements and calculate the underfloor heating sizing correctly for your home, office or project.

Can we help?

Send us your details and let us advise you on the best Rointe electric heating solution to meet your needs.

The success of Rointe electric heating products is due to correctly calculating the size of each product needed. That's why we've developed the Rointe Thermal Coefficient (RTC) to help increase efficiency and savings.

Rointe Thermal Coefficient

The RTC calculates the number of heating elements needed for a property, based on its square metres and geographic climate.

By using this calculation we can determine the appropriate sizing for the most balanced consumption.

To calculate the required electric radiators, we need to distinguish between m2 and m3.


· For ceilings with a height lower than 3 metres, we use the R.T.C. (m2).

· For ceilings with a height higher than 3 metres, we use the R.T.C. (m3).


Calculation m2 – ceiling height less than 3 metres

Reference table for D Series, Kyros and Sygma radiators in m2

Reference table for Kyros and Sygma short radiators (reduced height) in m2

An official Technical Study should be conducted before any installation of a Rointe heating product is carried out. The calculations on our online tool and reference tables are estimates and should be regarded as such.

Calculation m3 – ceiling height more than 3 metres

Reference table for D Series, Kyros and Sygma radiators in m3

Reference table for Kyros and Sygma short radiators (reduced height) in m3

In order to achieve maximum comfort and energy efficiency, several factors need to be considered to calculate the correct Rointe product size. Even though your heating installation could be a house, apartment, office, hotel or other property, it's important you know and understand the parameters considered before sizing or purchasing a Rointe electirc heating system.


The orientation of a room has an impact when calculating the heating size. For example, south-facing homes have an advantage over other others since they have greater contact with sunlight and warmth.

Climate zone

The UK has a varied average temperature range. Depending on the area, the country is divided into 4 climate zones, therefore it's important to consider where the heating installation is located.


Insulation plays a key part in maintaining a stable temperature in your property and can increase energy savings. A more insulated room will be more efficient and require less energy to heat.


If more than 1 product is required, they should be distributed evenly e.g. a 21m2 room needs 18 elements, made of two 9 element radiators with equidistant space between them.

Build & furnishings

The type of room or property has an impact on efficiency since they have characteristics that make them more or less vulnerable to heat loss, e.g. attic or kitchen. Stairs and furniture also play a key part in sizing.

Do you need help with a heating project?

No matter the type of property (hotel, office, public building etc.), if you’re thinking of switching to our low consumption electric heating ranges, then get in touch.


We can recommend specific products to meet your demands, conduct on-site visits and provide our expert knowledge and opinion on the best solutions for energy efficient heating.


This service is free of charge and ensures a tailor-made, quality installation that’s designed just for you with the best possible efficiency.


Call our Sales & Projects department now on 0203 321 5928 or send us your details using the contact form.

Where can I buy Rointe products?

If you already know the products you need, find out how to buy here:

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