Updated on: November 13, 2025

Infographic for blog: do's and don'ts of fitting a radiator

Fitting a Radiator the Dos and Don’ts

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At some stage in your life, it is likely that your home will require a new radiator fitting. Some decide that fitting a radiator is best left to a plumber. This is a smart decision if you are not confident enough to complete the project yourself. Whilst it is a project that can be completed by a competent DIY hobbyist, it is always worth getting advice from an expert before completing the task, especially if it is your first time.

At GK Plumbing, we specialise in all things plumbing and heating, helping to keep your home warm and functional in those colder months. Discover our guide to fitting a radiator, and more importantly, the dos and don’ts.

Why Do Radiators Need Replacing?

There are a number of different reasons why radiators sometimes need replacing. Visual wear on the old one is a key reason, especially when homeowners are renovating their property. However, the main reason is that the original radiator is not heating up and is, therefore, running inefficiently. By keeping a radiator that is not working properly you risk increased bills and a house that is a lot colder than it should be. Whilst the other radiators in the house will work towards warming the area that the inefficient radiator is installed, they will be unable to effectively lift the temperature to the desired degree set on the thermostat for the affected room.

It is important that you use the right tools and techniques when fitting a radiator. We have found that most homeowners have difficulties taking the original radiator off because the valves have not been supported properly.

Before installing a new radiator, some plumbers will advise that a power flush is completed. This can resolve the issue with a radiator. However, if the radiator still fails to run successfully after a power flush, fitting a new radiator to existing pipes is the next option.

Radiator Installation for Beginners and DIY Hobbyists

To keep you safe when trying to complete a radiator installation yourself, we have put a step by step guide together. Just to remind you, if you are not confident, call a professional plumber. At the same time, if you do attempt the project yourself, it is a wise idea to write down each step that you complete just in case you accidentally damage anything and require a plumber to come and fix any problems.

Before we begin, we recommend that you have the following tools available.

  • New Radiator
  • 4 x Wall Fixing Brackets (for guide one)
  • Wall Plugs (for guide one)
  • Tape Measure
  • Pencil
  • 2 x Spanner / Wrench
  • Drip Tray
  • Bucket
  • Large Allen Key
  • Hammer Drill (for guide one)
  • Steel Wool
  • Cloths / Rags
  • PTFE Tape
  • TRV (Optional)
  • Cup / Small
  • Radiator Bleed Key / Flat Head Screwdriver

Tools for Radiator Installation

How much you need to do to install a new radiator depends on whether you are directly replacing an outdated one or are completely installing a new one onto a different wall. If you need a radiator to be installed on a completely new wall and you are not a trained plumber we recommend that you call a professional. This will save you from making any mistakes and will also stop any unnecessary stress coming your way.

If you intend on installing a new radiator that is the same size and style as your original and would like to try yourself, then you can follow our guide. Installing a radiator that is the same as your original is more simplistic and the guide describes how to mount a new radiator onto already existing mountings.

Before you begin be sure to check your wall for any obvious issues. These include cracks or crumbling plaster. If you do have any defects on your wall be sure to fix them before you proceed with the installation.

Fitting a Radiator on a New Wall

If you intend on fitting a new radiator onto a new wall and you have never done this before, we recommend that you either call a plumber to do this professionally or do it with the support of a trained plumber or heating engineer. Whilst it is possible and there are a number of websites showing how to do this, there can be unforeseen problems that can occur. The last thing we would want is an emergency plumbing call out to fix an issue that would cost more than it would to have fitted the radiator in the first place.

Whilst we encourage homeowners to attempt simple projects such as changing taps, we do recommend that when it comes to your heating you call in a professional.

Guide – Removing Current Radiator and Fitting New Radiator to Existing Pipes

Before you begin the installation you must remove the current radiator. Below is a step by step guide on how to do this before the installation begins.

1. Turn Off the Radiator

Close the radiator valves by turning them clockwise until they are firmly turned off. This will cut the radiator off from the system stopping any water flowing through the radiator.

2. Position Towels and Bowl Under the Radiator

To avoid ruining the carpet or flooring under the radiator, please place towels and a bowl under the valve. This will allow the water to pour into the bowl and for it to be safely poured away later.

3. Undo the Radiator Valve Using Grips and an Adjustable Spanner

Now you have your bowl and towels positioned under the valve you can start to undo the radiator valve nut. Do this gently to avoid any unexpected accidents.

4. Drain Water from Radiator

Simply put, just let the water drain from the valve into the bowl thus emptying the radiator of any excess water.

5. Use Bleed Key to Empty Last Drops from Radiator

Using a radiator key or an appropriate tool such as a flat head screwdriver, open the top valve to help fully drain the radiator. Simply turn anti-clockwise. Remember righty tighty, lefty loosey.

6. Close Bleed Valve and Undo Valve Nut on Other Side

Now that you have completely drained the radiator, close the bleed valve (Clockwise / right) then move to the valve on the other side and start to undo the nut on that side.

7. Tilt Radiator to Pour Out Any Remaining Water

Now that the radiator is free from the nut on the other side, tilt the radiator to gently pour any remaining water. The water may be a rusty brown colour but do not worry about this as it is normal. Be cautious when lifting as some radiators can be extremely heavy. We advise using two people to lift if you can, even if you are strong enough to lift on your own.

8. Completely Remove Radiator From Wall

Once all the water is removed from the radiator, push tissue paper into the valve inlets. Now you can fully remove the radiator from the wall by lifting it up from the brackets. Again we recommend that you ask for help when doing this to prevent any injuries to your back occurring.

Installing New Radiator to Wall

If you have chosen a radiator that is similar to the one you originally had installed on the wall then there is no need to inspect your wall before the installation. However, if you intend on installing a new type of radiator that could be heavier than the original you must fully inspect the wall, especially if your wall is a stud wall. Our advice to you is to go with a radiator that is similar in weight and size to the original one you had to avoid any issues. Choosing one that is identical to the original will also mean that you do not need to reorientate your valves.

If you are installing a new radiator that is identical to the size of your original radiator, the brackets will already be on the wall. You will simply need to line up the radiator against the brackets and slot them into place. There will be no messy drilling; you simply need to hang the radiator.

We recommend that you use two people to hang the radiator, no matter how big or small. This helps with balance, weight and will prevent you from damaging the radiator when lifting.

GK PLUMBING CAN COMPLETE RADIATOR INSTALLATIONS

Whether you’re trying to install a radiator yourself and need advice, have tried and need help or are looking for a professional to install the radiator for you, GK Plumbing & Heating can help. We are based in Aylesbury and have trained plumbers operating throughout the whole of Buckinghamshire. We even have hard-working lads based out in Oxford, Milton Keynes and High Wycombe.

Give us a call today on 01296 434 785 and speak to owner Gareth Knell who has been in plumbing since his apprenticeship in his teens!

Alternatively, send us a message through the website and we will get back to you with any answers to questions you may have.