How to use a BTU Calculator? (Delta T 50°)

Where can I find a BTU Calculator?

If you’re planning to upgrade your current heating system, you may want to consider using a BTU Calculator to find out roughly how much power you’ll need to heat a particular room. We have a handy BTU Calculator on our website, which can be found by navigating to Help Centre > BTU Calculator (located at the top of our page). Alternatively, this link will take you straight there:

What you’ll need?

You’ll need to know the length, width and height of the room you’d like to measure the BTU’s for. You’ll also need to take into consideration what “Wall Type” you have, whether it be brick cavity, insulated brick cavity or 105mm-220mm solid brick.

Room Type

Room type is important because it dictates how much energy is required to heat a room sufficiently. For example, a living room should be nice and warm because it’s the communal area of the house. You won’t want your kitchen to be extremely hot, if you’re only going to be doing your cooking in it.

When figuring out the BTU’s for big rooms, you might want to think about how big the space actually is. Sometimes it is better to have two radiators sharing the BTU’s rather than having one radiator doing all the work. This is sometimes common in “L” shaped hallways. Let’s say you work out the hallway to be 8000 BTU’s. If you install one radiator in the hall, the other end of the hall might be a considerable amount colder. The best thing to do would be to install two radiators worth 4000 BTU’s each, sharing the heat together.

Remember, you can always opt in for thermostatic valves, and have true control of the temperature in your home. Standard valves will get the job done at heating your home. However, the thermostatic valves have a manual control setting from 0 – 5 which allows you to control the temperature of individual radiators or towel rails, which is a win all round!

Where is your room located?

You will need to consider what is above & below your room. Do you have a solid concreate floor, or do you have a heated room underneath you? These are all things that affect the amount of heat your room with require to be efficient.

Does your room have windows and outside walls?

When you are measuring your room, make sure you note how many outside walls and windows there are. Outside walls and windows will draw heat. Double glazed windows are great at holding the heat in and so are insulated walls. If you have single glazed windows or solid brick walls you may have a lot of heat escaping.


Once you have all the fields selected and completed, you can then view our estimate on how much BTU’s/Watt’s we recommend. This is a great start to choosing your perfect radiator. We have all kinds of designer radiators capable of high and low BTU output.

Discover our range of radiators here!

To learn more about these products or for any enquiries you may have please don’t hesitate to contact us at or on 01492 573738.

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