It’s an exciting time when you have made the decision to add an extension to your property. The planning stage is the first step and the most important process there is. You will need to consider many factors, and one of the key considerations is ensuring the comfort of the extended space. This includes addressing the heating needs, so think about how you’re going to add radiators to an extension.

Calculating the heat output for a new extension

When making your choice on how you will heat the room, it is important to remember that it is not as simple as just choosing a great design, you will also need to ensure that the heating system chosen will be able to heat the space efficiently. To do this, you will need to calculate the heat output required within each room;, this is measured in British Thermal Units per hour (BTU/h). Our team are best qualified to work this out accurately for you. However, you can follow our basic guide at the end of this article that will help to give an indication.

How to calculate heat output in BTU

Calculate the cubic volume of your room in feet. This is calculated by multiplying the height, width and length of your room. After that, multiply the figure by the following values for a rough estimate.

Room Multiply by
Lounges and Dining Rooms Multiply Cubic Feet by 5
Bedrooms Multiply Cubic Feet by 4
Common Areas and Kitchens Multiply Cubic Feet by 3
For Rooms Facing North Add 15%
For French Windows Add 20%
For Double Glazing Deduct 10%

If you’d prefer a simpler way to work out the heat output and size of radiators you will need to adequately heat your new extension, why not use our handy heat output calculator?

How many radiators will I need?

Once you have calculated your BTU/h for each room, you will then need to consider how many radiators you require and the location they need to be placed in. It is standard practice to place radiators in the coldest part of the room, which tends to be either on an outside wall or below/adjacent to a window.

As a general rule, the larger the radiator, the greater the heat output. If your new extension is going to include a new bathroom or cloakroom, don’t forget that a heated towel rail is a necessity in all modern bathrooms. There are two main types: those which simply warm your towels and those which also act as a space-saving heater, making sure your entire bathroom is always cosy and warm.

Stylish radiators for a new extension

Now you are ready to tackle the design aspect of the project. Designer radiators are a stylish alternative to the standard ‘pressed steel’ options that you see in most modern homes., They can offer an aesthetically pleasing focal point to the room and can fit in with your style of decor. There is a broad collection to suit all tastes, including a variety of elegant classics through to a number of futuristic, colourful models. If you are looking for a more traditional feel but, still want to keep the efficiency of modern styles, there is a fabulous range available that will not look out of place in even the most historic of houses.

Energy efficiency is of the utmost importance, both from an environmental and financial point of view. Radiator technology is improving all the time, which means the ‘low energy and high output’ designs are now a hugely effective option, especially where you have a limited amount of wall space, like in a bathroom. Another great option to consider are thermostatic radiator valves (TRVs), which enable you to not only manually set the temperature of individual radiators, but also regulate heat output, automatically reducing flow to the radiator when the surrounding air temperature rises too high.

We hope that this guide has been helpful. If you require any assistance with your project, including aspects like adding radiators to an extension, please contact our friendly team.