What is a BTU & Why Is It Important?

As you explore the Radiators Direct site, you will see that ‘BTU’ is frequently used on our product pages, and it is important to know when it comes to shopping for home heating.

What does ‘BTU’ Stand For?

BTU stands for 'British Thermal Unit' and is a measurement of thermal energy. It is the standard output (heat) measurement for radiators and towel rails (except electric heat sources).

What Does BTU Mean For Radiators?

Fundamentally, the BTU attributed to a radiator is a simple way of numerically displaying how much heat the radiator emits, so you can make an informed decision when buying radiators and ensuring they will heat your space effectively. Whilst style, colour and design are important, knowing how many BTUs are required will allow you to choose a radiator (s) that will heat the room efficiently - taking the time to calculate the BTU requirements of the room you’re looking to heat is integral.

How effective the radiator will be though depends on factors such as the size of the room and how well-insulated it is. A radiator’s ability to transfer heat will depend on its material, size and surface area as well as the water temperature within the system.

How to Calculate BTU for a Room

There are many factors that will affect BTU and it can be daunting to try and work this out. However, the good news is, that we have developed our own BTU Calculator to take care of the calculations for you. Our calculator is completely free to use and will make working out the required BTU amount nice and simple.

Once you’ve entered your measurements and specifications, our BTU Calculator will tell you the combined BTUs (Heat Output) your room requires to be heated effectively. Our BTU Calculator also provides its’ calculation results in Watts, for reference against electric radiators and towel rails.

Once you've worked out your heat output requirements, make a note of the results and keep them to hand. From here you can view our range of radiators and/or heated towel rails whilst referencing the output displayed on each against your calculations, this way you can ensure that you're choosing the perfect radiator/towel rail for you.

Important to Remember

• Our calculator will show you the combined output required for the provided room measurements; in the case of larger rooms that require more than 1 radiator, divide the calculated output by how many you need.

• All of our BTU ratings are displayed at Delta T50. Delta T50 is the UK standard for all domestic gas boilers and is set to allow professionals, end-users and consumers alike, to make a fair and reasonable comparison of radiator and towel rail outputs from various suppliers and across a mix of product types. Many newer boilers will operate at a lower Delta T rating, which will affect the BTUs being output, and subsequently, the size of the radiator required. Check out our Delta T Converter here which will allow you to convert BTUs to various Delta Ts.