How to Replace an Old Radiator

An old radiator in a rundown bathroom
29 September 2023 181 view(s) 5 min read
How to Replace an Old Radiator

Thinking of replacing an old radiator?

Here are some guidelines to help get it right!

There are many reasons why you might decide to replace the radiators in your house: it may be necessary, for example, to carry out major changes to renovate the whole house, so in addition to replacing the old boiler with a condensing heat generator, you might also need to change your old radiators for radiators more suitable to operate at lower temperatures or that enhance the look of the room or age of the property. Today there are a lot more options available to us, you could be looking at traditionally styled steel multicolumn, high-design contemporary radiators or aluminium models with excellent thermal properties and efficient energy use.

Often radiators are replaced as part of the whole renovation of a house or part of it (such as the bathroom) and the old radiators are either damaged, rusty or simply no longer in line with the new interior style of the room.



​The most suitable time of year for an activity of this kind is the summer when temperatures rise and we won’t miss the heating when the system is being adjusted during renovation work. Having to turn the system off in cold weather adds extra pressure to get it completed quickly and could cause the job to be rushed.

Where to Start and Which Radiators to Choose?

​If the replacement affects all the rooms of the house, it is recommended to start in the living areas, the most "visible and frequented". Usually, these rooms are larger, so you need radiators that have good outputs, like multicolumn radiators (or similar). Thanks to their sectional nature, they can be specified to work in any space, offering the ability to select different heights, depths (number of columns) and widths (number of elements). For the bathroom, where the heat requirement is generally lower, we recommend a classic heated towel warmer. The choice in design terms is very wide: you can choose between round tubes with different diameters, flat or slatted tubes, or square sections and to add to the range of styles you can create a wide range of colours and special finishes are available.



Calculating the Right Output Is Important

​It is essential to understand what output requirements the radiators have to meet in order to heat your rooms to a comfortable temperature, in order to do this we calculate it on a number of factors; the exact size of the room in which it will be placed, the type of insulation of the room, the number and type of windows (French windows, skylights, Double gazed etc) all these factors affect the amount of heat needed to keep the room at a set temperature.  The best solution is to contact a professional, for example, a heating technician, who will be able to calculate the correct heat requirement of the room or of the whole house and will be able to calculate the right sizing of the new radiators and the boiler.

Alternatively, you can work out a guide output using an online calculator, you can find ours here which can help calculate a rough indication of the output needed to heat a room. However, it is always a good idea to have these checked by a professional.

The space in which the new radiator is to be installed must also be taken into account and, very importantly, it must be borne in mind that it is unlikely that the position of the pipework of the radiators to be replaced will be the same as the new ones, consult your installer they will often be able to identify how best to achieve what you are looking to do with the least disruption.
Let's look at some examples.

If the radiator is installed under a window or in a tight space (such as near a corner of the room), it is important to be able to calculate the height and width of the radiator;

When replacing an old radiator, the most important measure is the distance between the centres of the two pipes in the system

For easy replacement of the old radiator, it is essential to select a new model with the same pipe centres as the one you want to change.



The pipe centres are also an indispensable measure for the installer who has to install a new heating system.

The pipe centres can be vertical (the system pipes are positioned one above the other with the flow at the top and the return pipe at the bottom), horizontal (the system pipes are positioned one on the right and one on the left side of the radiator, the most common configuration in the UK) or horizontal under the radiator. The latter solution is very practical as the valves do not take up space beyond the side profile of the radiator, very helpful when space is tight. 

Contact A Professional

For help choosing your new radiators, you can work with your architect or interior designer and maybe visit a specialist radiator or bathroom furniture showroom with them to view the products and choose the one most in line with your tastes and the style of the house. Once the choice has been made, a good plumber should have no difficulty in using the pipe centres and other technical details to confirm the final size and complete a professional replacement.


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