How To Replace A Radiator

Whether you want to replace or upgrade your radiators, our step-by-step guide walks you through the process.
Written By: Richard Morgan | Updated:
How To Replace A Radiator
Richard Morgan/DIY Works

Depending on your DIY experience, the process of replacing a radiator isn’t too difficult. It’s made even easier when there isn’t any pipework to alter underneath the floorboards.

However, if you aren’t experienced but want to see what a professional has to do to replace a radiator, the guide below will walk you through the replacement.

Assuming you know the radiator size you need, below is our advice and the steps required to replace a radiator.

Advice Before The Replacement

As you will be removing the old radiator, it’s highly advised that you check the condition of the wall. If there are any areas of cracking or crumbling, you may want to get the wall plastered or use some wall filler before replacing the radiator. You may also want to apply a fresh lick of paint while removing it for the finishing touches too.

Different Sized Radiators

If you are installing a larger or smaller radiator than the current one, you will need to make some pipe alterations. If this is the case, you are advised to call a professional plumber to do this for you. Not only will the pipework need to be altered, but you will also need to pull up the floorboards and even cut into any wooden joists.

As you can see in the photos below, the replacement radiator was much larger and had pipework alterations under the floorboards. Luckily, we ensured this work was done before laying down the new carpet.

how to replace a radiator with a smaller one

Richard Morgan/DIY Works
How To Replace A Central Heating Radiator

Richard Morgan/DIY Works

What You’ll Need

If you are replacing the old radiator with a same-size replacement, below are the tools and parts you require.

How To Replace A Radiator

1. Turn off Your Heating & Isolate The Radiator

To begin replacing a radiator, you will need to turn off the central heating and isolate the old radiator, which can be achieved by shutting off the valves at either end. If you have a manual valve, you will need to turn it clockwise until it no longer turns. If it’s a TRV, you simply turn it all the way to the “off” position.

2. Drain The Radiator

After isolating the radiator, the next stage is to drain it into a bucket or container. Using an adjustable spanner, simply loosen one of the swivel nuts that connect the valve to the radiator. You may also need to use another spanner to hold the valve securely to prevent the pipework from also turning along with the valve. Once complete, you can then open the bleed valve at the top of the radiator and drain away all the water.

3. Lift Away The Radiator

Once the water has drained out of the radiator, you can begin to lift it away from the bracket. Before completely removing it, it’s advised that you tip the radiator in order to remove any remaining water. If the radiator is rather large, you may wish to ask for help as it can be quite heavy.

4. Replace The Existing Wall Brackets

When you purchase a new radiator, they often come with new wall brackets, and it’s good practice to use them rather than the old ones. Therefore, using your screwdriver or drill, remove the old brackets. You can then continue to use a masonry drill bit and red plugs to install the new brackets to the wall (assuming the condition of the wall is in good working order).

5. Replace The Valve Connectors & TRV’s

Whether you replace or keep the old connectors, you will need to install them onto the new radiator. If you are keeping the valve connectors and TRVs, you will need to clean them up with wire wool. As you connect them (new or existing valves), you will want to use PTFE tape around the threads to ensure they are completely watertight.

6. Fix The New Radiator To The Brackets

Now that the new radiator is all set up, you can attach it to the newly mounted brackets on the wall.

7. Reconnect All Connections & Bleed The Radiator

Once the radiator is on the wall brackets, continue to connect the valves and reset them. You will also need to open the radiator’s bleed valve to allow any air to escape and help fill the radiator with water. Once complete, check all the valves and joints for any leaks and double-check that everything is tightened correctly.

8. Enjoy The Heat

You can then step back, admire the shiny new radiator, and test that it’s heating up correctly.

How Much Does It Cost To Replace A Radiator?

If you have read our guide on replacing a radiator and decided it isn’t something you are tempted to try, you will need to get a professional plumber to do it. However, how much does it cost to replace each radiator?

Excluding the cost of the radiator itself, the cost to replace a radiator can include:

  • Like for like replacement radiator – £80 to £150
  • A smaller or larger replacement that involves pipework alterations – £200 to £300
  • Replacement radiator moved across the room – £250 to £300

The prices do vary due to the areas that you live in and any extras or repairs that may be involved during the replacement. Most plumbers may also offer a discount if you replace more than one radiator. This is due to the fact that they only need to drain the central heating and repressurise it once, which is often the most time-consuming aspect of replacing a radiator.


Although you can attempt to replace parts of a radiator or even paint the radiator, if it isn’t pumping out enough heat, it’s advised that you replace it. As long as you are replacing the radiator with a same-sized replacement, it isn’t too difficult. The only difficultly comes when the pipework needs to be altered in order to cater for the larger or smaller radiator size.

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