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How to choose the right radiator

Choosing the right radiator can be difficult considering the many different types and styles on the market, but at the end of the day it comes down to making your home the most comfortable it can be. For this, you need to consider which sizes and materials are best for your home, and understand where to install your radiator.

Calculate your radiator size

Before making any radiator purchases, its essential to calculate the heat output in BTU (British Thermal Units) required to heat a room. You can make a rough estimate using the following calculation (N.B. measurements all in m):

Length of your room x width of your room x height of your room x 153

There are a few factors which can alter the result from your calculated BTU output. These factors can include whether the room has double glazing or insulated wall cavities. We’ve supplied a table below to help you adjust the outcome of your BTU calculation. Adjust your room dimensions with the values that apply to your home before multiplying them with 153.

FactorAdjust by
For solid floor-10%
For non-insulated cavity walls+10%
For foam-filled cavity walls-20%
For upstairs bedrooms-25%
For double glazing-5%
For two outside walls+15%
For three outside walls+40%
For northern aspects+10%
For missing loft insulation+15%
For high ceilings – 3m+20%

You can use a radiator size calculator to do this for you, but it’s recommended to call a Gas Safe registered plumber or engineer to take accurate measurements and gather the correct radiator sizes for you. It could be the difference between a poorly heated room or an overly heated room, the latter of which could in the worst case lead to energy waste.

Typical radiators are between 300-700mm high and 500-3000mm in length. Remember, the larger the radiator, the larger the heat output, so it’s important to record the correct measurements.

What are radiators made from?

The material used for your radiator is also important since some radiators take longer than others to heat up. The most common radiators on the market are made up of a traditional steel design. However, you may find that you want to either go for a more lightweight option or a material which holds heat for long periods of time, including after you’ve switched off the heating.

Aluminium radiators are a lightweight choice and heat up quickly. You will normally find this type of radiator mounted on most walls in the form of towel rails or in some rooms as part of the interior design. They don’t require a large amount of water and are perfect for smaller spaces, which is why they’re often the preferred choice for bathrooms. However, while a great lightweight choice, note that aluminium doesn’t retain heat for long periods of time.

Cast iron radiators, in turn, take a lot longer to heat up, but they do benefit from holding heat for a long time after being switched off. They weigh a lot more than aluminium radiators, so it’s important to consider where you’d like to install a cast iron option. You will also find that a matt finished radiator built from cast iron will emit more heat than one with a glossy surface.

You have probably seen a lot more choice online in the realms of designer or contemporary radiators. These are a great choice if you are looking to get a radiator to not only match your personality but also your interior design. You can purchase designer radiators in a wide range of colours and styles, with the option of a completely new material like stone or glass. A lot of these radiators can be wall mounted or floor standing depending on the style and your personal preference.

Still looking for more information on radiators? Check out out radiator guide here.

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