Size isn’t everything—or is it when it comes to buying a radiator? Read on to discover why the size of your chosen radiator could make all the difference.
When it comes to radiators, size really does matter and it is one the primary factors you should take into consideration when buying a new one. Of course, the style, material and compatibility with your heating system all matter too, but size plays a central role in ensuring your room is sufficiently heated by the radiator you choose.
Getting the balance right
If your perfect radiator is too small, it will struggle to warm the room as it won’t be able to produce enough heat. This will place extra strain on the boiler, while also increasing your heating bills as you keep your heating switched on for longer than necessary.
When a radiator is too large, it’ll produce too much heat for the room and create excessive energy, which is not ideal for the environment and, again, could increase the cost of your bills. A radiator that is too large for the space will also likely take up too much room on the wall and won’t fit brilliantly well with the rest of your decor.
So, you've picked out a beautiful new radiator, but is it the right size for your room?
What size radiator should I buy?
So how do you find the right balance? The answer is to calculate the BTU output for the room the radiator is being installed into. BTU stands for British Thermal Unit, which represents the level of heat required to sufficiently warm up the space.
The higher the BTU, the more heat that is required for the room. However, no one room is the same, and it can differ from house to house, which means you will have to do a few simple calculations to find the radiator size you need.
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Take measurements of the length, width and height of the room in metres. For rooms that have angled walls or alcoves, split the room into rectangles and measure these separately, adding them all together at the end to get the total length and width.
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Multiply the width by the height and length of the walls to get a subtotal.
You will also need to consider any heat loss in the room via windows or doors (and if they are single or double glazed).
There are also additional standard ratings to add to the calculation as below.
| Room | Double glazing | Single glazing |
|---|---|---|
Now that you have all the measurements you can calculate the BTU for the room.
As an example, imagine your measurements for a double bedroom were 4.2m (L) x 4.4m (W) x 2.5 (H). Multiply this together to get a total of 46.2.
If you have double glazed windows in the room, this needs to be multiplied into the calculation: 46.2 x 108 = 4989.6. Round this up to the nearest figure, which means the BTU for the room is 4990. Now, all you need do is find a radiator with a similar level of output.
For larger rooms, you won’t necessarily have to find a single radiator for the space, especially if the BTU is quite high. The total BTU can be split across 2 radiators—just ensure that, combined, they reach the minimum requirement for the room. Smaller rooms will usually only need one radiator, and it should be easy to find the right one for your home.
To find the perfect radiator for your room, simply check its BTU output
More heating advice
Like to spend time researching a product before buying? We hear you! At Victoria Plum, you’ll find all the expert advice you need when it comes to heating, including an in-depth radiators buying guide and a comprehensive heated towel rail buying guide too. Could underfloor heating save you money? Find out by reading our blog.
If you are the type of person who likes to roll up your sleeves and do the hard work yourself, you’ll find a step-by-step installation guide for radiators, instructions on how to replace radiator valves and a guide to fitting heated towel rails too. Browse all our heating advice and find out everything you need to know.
Shop radiators
Now you know which size you need, why not browse our wide range of stylish radiators. From compact vertical designs to traditional style models, you’ll find a superb selection all at affordable prices. Click on the image below to begin shopping.
