★ Judge.me Reviews

Why Should You Choose Us?

191 reviews

Excellent radiators for the towels. We love them

The best towel radiators ever. We’re installing these in our second bathroom
As they’re so brilliant in our wetroom.

Good heated towel rail

This towel rail radiator looks good and seems to work well so far.

Fast service

When I placed the order, I was told that it was out of stock but would be available end of June. I was surprised, therefore, when the towel rail arrived the next day. The heater and fittings arrived separately two days later. It would have been nice to have known that they would arrive separately, but excellent service otherwise.

Pisa towel rail

Great price, product and delivered on time.
Perfect experience

BTU Calculator | 3 Easy Steps To Calculate Radiator Size
Free Delivery To Mainland UK

Not sure what you need? Call our customer help line on 0330 058 6489 to discuss your needs.

Need help? Call us on:0330 058 6489

BTU Calculator - Heat Output Requirements & Radiator Sizing Guide

We would like to proudly present our brand new BTU calculator!

If you are unsure about the heat requirements for a room in your home then you can use our BTU calculator to find out how much heat you require to keep it toasty warm all year through!

Step #1

Please select your desired room

Step #2

Please select the correct measurement type and input the height, width and length

Step #3

Please check the following questions and correctly answer as this will affect your quote.

North Facing Windows?
Patio French Doors?
Double Glazing?
Total: 0 BTUs
Total: 0 Watts

The boring bit is out of the way and now you know your required BTU's - we now invite you take a look at our extensive range of unique and modern designer radiators...

TOP TIP - Filter results by BTU output to show radiators suited to your heating needs

Why settle for a boring white radiator?

Vertical Designer Radiators

Vertical Radiators

Horizontal Designer Radiators

Horizontal Radiators

Designer Bathroom Radiators - More Stylish And Beautiful Than Ever

Bathroom Radiators

Designer Towel Rails

Designer Towel Rails



There are several factors which you must consider when choosing a new radiator for your home. Here, we will help you get the right radiator for your home.


Radiator Size BTU Calculator

 You may find yourself asking such questions as:

  • What is a BTU?
  • What size radiator do I need?
  • How do I calculate radiator size for a room?
  • How many watts are in a BTU?

Here, we will be dispelling the mystery behind the elusive BTU measurement and how you can use our BTU calculator to find out which radiator(s) will be perfect for your home!


What is a BTU?

Let’s start with the basics - A BTU (or British Thermal Unit) is a traditional unit of heat which can be defined as the amount of energy required to heat 1lb of water up by 1 degree Fahrenheit. This is sometimes hard to imagine, so a common analogy to explain this is to compare it to the energy given off by a single burning match (Source)


Burning Match BTU Heat Output


If the concept of the BTU is still a little baffling, you can always refer to the more traditional Watt to calculate heat output. All that you need to remember is that 1 Watt of energy is equivalent to 3.41 BTU’s. Alternatively, if you have a BTU measurement and would like to find out the heat output of your radiator in Watts all you would need to do is divide the BTU’s by 3.41.


What size radiator do I need?

There are several factors which you must consider when choosing the right radiator for your home such as…


What heat output does the radiator need to be?

What size should the radiator be?

What style and colour will suit the desired room?


The heat output required for any room within your home can be calculated with the use of our very own radiator size calculator! This BTU calculator uses the dimensions of your chosen room to give a BTU requirement for the entire room; considering several variations such as double glazing, north facing windows and patio French doors to help calculate radiator size.


Once you have entered the dimensions of your room and accounted for the additional heat loss variations you will have a final BTU reading which accounts for the total heat requirement for the chosen room. This value does not represent the total BTU requirement for a specific radiator, but rather the total BTU’s required from the addition of all radiators within that room.


Choosing your radiator

The next step in determining the heat output and size required for your radiator is to determine how many radiators you would like to heat your desired room. In most cases 1-2 radiators will suffice, however for larger rooms you may require more. The amount of BTU’s required per radiator will depend on how many radiators are within the room – so divide the total BTU requirement by the number of radiators to calculate the average BTU’s required per radiator.

We have a large range of designer radiators which you can filter to show only radiators with the amount of BTU’s that you require.

Different rooms not only have different BTU requirements but also have aesthetic requirements, for example some of our Horizontal Radiators would be very well suited for a living room or hallway, but may look out of place as a bathroom radiator. Luckily, we supply a very diverse range of radiators to suit every room in your home – from our space saving Kitchen Radiators to the popular and contemporary Terma Ribbon Vertical Radiator, which can be used in living rooms, hallways and kitchens.


You can also add a towel rail element to convert the towel rail to electric or dual fuel

 If you would like some more tips on how to heat your home in style take a look at our previous blog: ‘Consider your radiator as part of your room design'.


Statement Collections

Now that you know the required heat output for your home, which radiators will you choose? Browse our collection of modern designer radiators and towel rails:



  Terma Ribbon Radiator


Towelrads Cobham Towel Radiator  Terma Jade Towel Radiator



This calculation is simply an estimate, please refer to your plumber if a more accurate reading is required. Our calculations are only estimated and are based on information you provide. The BTU calculator can only process the most common factors that affect heat loss and may not take into account all factors relating to your particular requirements. Any results provided by our heating calculator should not be considered 100% accurate, and we accept no liability for any errors resulting from the estimates given. Calculations based on Delta - T 50°C (Δ-T50°C).

Queensgate House, Bracknell, Berkshire, RG12 1RB   |  Company No. 10757797  |  Vat No. 245441516

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