Skip to navigation Skip to content

A Guide on How to Replace a Radiator

Replacing a radiator isn’t something we think about much, and often in our redecorating endeavours, we simply go around our old and faithful units.

Sure, changing a radiator is not the simplest DIY job but it’s by no means impossible. This handy guide on how to replace a radiator will prove to you just that!

As one of the country’s largest independent heating specialists, we know a few things about how to replace a radiator and we’re here to reveal all.

So whether you’ve just picked out a radiator replacement from our online store or have one ready, let’s get heated. And if you hit a roadblock along the way, just give our experts a ring to get yourself back on track!

Ready to add the knowledge on how to replace a radiator to your DIY repertoire?

There’s no turning back now!

So, When Should You Replace a Radiator?

The time for replacing your radiator depends on the quality of your installation, your unit, and your upkeep.

If you are noticing uneven heat distribution or a total absence of heat, then it’s likely done for. Why else would you be reading this – pleasure?!

Sure, you might coax it through a few more tired years, though it may well catastrophically fail in the depths of winter and over Christmas, when a home visit is as rare a sighting as one of Saint Nick himself!

Radiator prices are forever dropping so why neglect it any longer?

Why Should You Replace a Radiator?

Radiators aren’t like socks, that’s for sure – we see as many 50-year old units as we see new radiators.

Radiators are one of those remarkable things that have the potential to last aeons – like those gnarled yet adorable Galapagos tortoises, centuries old yet not lost any of the pep in their step – but may also collapse after a few mere years of use.

So if it’s still ticking, you’re likely replacing your radiator as a part of a larger DIY project. We like your thinking!

And if you’re looking for new designer radiator ideas, have a browse of our leading best price radiator styles and options. There’s a reason why we’re industry leaders.

Have a look at some of our most popular radiators below.


No More Delays! Time to Replace Your Radiator

As we mentioned, radiator installation is not the easiest job but we believe in you!

However, if you do have doubts then it’s best you call an expert. We can’t be responsible for those wallpaper-destroying jets, pools of black water or icicles on the end of your nose!

If you’d like a recommendation for a local tradesman just give us a call to see if we can help you find one of the best-rated plumbers in your area. Our extensive trade community can each perform your radiator replacement to the very highest standards – that’s why they have the Only Radiators seal of approval.

Still determined? We salute you!

Ready to learn about how to replace a radiator?

Well, let’s get cracking.

Tools For Replacing A Radiator

You’re going to need a fair few tools to ensure your radiator replacement goes smooth. Some parts will make perfect sense yet others may surprise you. Replacing your radiator is a bit like a trip to the doctor in that way.

You will need:

  • New radiator
  • New radiator brackets
  • 2 adjustable spanners
  • A radiator bleed key
  • A digital detector
  • A hammer drill (for masonry) or a drill driver (for internal walls)
  • A masonry drill bit
  • Steel wool
  • PTFE (thread seal) tape

Other bits and bobs:

  • An old washing up bowl
  • Some old rags
  • A mate to lend a hand
  • A notepad and pen (trust us!)

Once you’ve gathered the above paraphernalia it’s time to start learning about how to replace a radiator!

Note: If you're planning on simply adding a radiator then you can skip right down to Step 4.

Step 0 – A Sure Foundation

We start here because it’s useful to point out and something that many forget. You do not want to fit your brand new radiator to a wall that’s not structurally sound, so please ensure it is!

If you see cracks or crumbling then that’s the job to do first – replacing plaster walls is a lot harder when your beast of a new radiator has just pulled them down entirely!

When you have a nice, solid location for your radiator replacement then it’s time to get stuck in!

Step 1 – Interdimensional

When choosing your replacement radiator it makes sense to choose one that uses the same dimensions as your previous unit. This will save a lot of work later on.

However, if the dimensions of your new radiator are different, it simply means making alterations to your pipework.

Step 2 – Drain Time

If your house features modern plumbing fittings then draining the system is a relatively simple task. Just clear away the flooring and skirting and we can get down to business.

With the central heating turned off, shut off the radiator valves by turning clockwise, or to the “off” position if you have a thermostatic radiator valve.

Those with a lockshield valve should remove the plastic shield and turn clockwise. Ensure you count the number of turns so you can set the same flow rate with your new radiator! Time to write some figures in that notepad, we reckon!

Now grab that old bowl and place it below the draining valve. Loosen the cap nuts connecting your radiator to the valve, which may take some welly so use the second spanner to avoid a slip that may well compromise the surrounding pipes!

Step 3 – Still Draining

Open the bleed valve with your radiator bleed key and loosen the connecting cap nut between the valve to drain out all of the water in the bowl. If the bowl gets full, temporarily tighten the bleed valve to empty the bowl for another round!

It may be surprising how much draining a radiator takes, as well as the colour of what comes out. If it’s an old radiator there’s going to be a lot of rust and grime build-up in the system. You really don’t want it all over your carpet, trust us…

Once empty, you can fully disconnect the opposite valve and free the radiator.

Step 4 – Out with the Old

If all along you were just planning on adding a radiator then now is the time to pay attention!

Grab your mate (these units are heavy – it’s not worth it Arnie!) and lift the old unit away from the wall. Take a second to tip it over the bowl to shake out any excess water, then stuff rags into both ends to ensure it doesn’t ruin your prize rug. For more information, take a look at our How To Remove a Radiator Guide.

Step 5 – What a Bracket

Now if the brackets of your new radiator have the same dimensions as your previous unit, there’s no drilling to be done. Phew!

But if you’re drilling into walls you first need to confirm what type of walls you have. There are two main types:


These are hollow-space walls with timber skeletons affectionately known as studs and noggins. It’s in the centres of these beams that you’ll find the strongest and best anchor points for your new radiator brackets.

Masonry and Brick

This heavy-duty option is more common in older houses and will provide a far more resilient base for your new radiator than studwork. If this is your wall type, you can really go to town when replacing a radiator.

When you’ve figured this out, it’s time to drill. Whip out your digital detector to ensure you don’t pierce anything important back there and use the correct drill bit for the walls you have.

Step 6 – In With The New

With your brackets fitted, now’s a great opportunity to fix reflective radiator tape to the wall that your replacement radiator will cover. This will bounce heat back into your room and lower those sneaky bills.

Now carefully remove your old unit’s valve connectors and clean with wire wool. Then wind your PTFE tape around the threads about 10-15 times to ensure a watertight seal!

Screw these into your new radiator fully and hang it on the wall. Et Voila! Pending some adjustments you can step back and admire your handiwork!

Reconnect and reset your valves using the numbers of turns that we hope you wrote down – some experimentation may be due if not, which is why we always recommend summer as the season for replacing a radiator!

Step 7 – Open the Floodgates

OK, now for the big moment. Time to let water enter your replacement radiator!

When you open the radiator bleed valve you can anticipate some gurgling – from you or the radiator, who knows? – as this allows the air to escape and the water to fill your new radiator.

When your bleed valve begins to bubble at the nipple, recheck all of your joins, pipes and turns one more time and then you are ready to seal it off once and for all!

Step 8 – The Finishing Touches

Your successful job is a great opportunity to service your other home radiators. We know, we know, it’s taken you hours but you’ll thank us later. And remember, you'll always have this handy guide on how to replace a radiator to refer back to.

Check all of your home radiators closely and keep an eye out for exciting opportunities such as radiator bleed valve replacement or changing a thermostatic radiator valve.

Then it’s time to run radiator rust inhibitor through both your new radiator and your existing home radiators. This fantastic liquid will minimise corrosion and protect your new radiator for the longest possible time! You can add a radiator inhibitor to your system at any time so why not do so while you’re in the zone!

Did you get stuck anywhere along the way? Did this article on how to replace a radiator leave some questions unanswered? Just give us a call and we’ll talk you through it!

The Brass Tax – What Replacing Your Radiator Costs

Depending on the tools you already have to hand, replacing a radiator is not as costly as you think!

We have designer radiators in a range of sizes to suit every room so take your time and find a replacement radiator that’s really special.

If you’d like to run your existing radiator’s dimensions by us for recommendations then please do. Our experts really can’t get enough of talking about radiators!

When Getting Heated is Good!

Learning how to replace a radiator and then replacing one, is an occasion when getting heated is the goal, so take a step back and admire your handiwork.

Crank up the heat and bask in the pulsing warmth of that slick new upgraded radiator unit. That’s all you baby!

Ensure you really enjoy it, because you aren’t going to want to be repeating the above process any time soon!

If you’re proud of your DIY radiator installation then why not share it with us to be featured in a future Readers’ Heaters picture blog? Just send your photos and accounts to

Your Leading Heating Source

As always, keep checking up on the Only Radiators blog time and time again for industry-leading home heating ideas, and sign up to our newsletter for exclusive news, money-saving tips, competitions and much more!

You might also like

Back to top