How to Replace a Radiator

Replacing a radiator is easier than you might think. Many modern designs come with everything you need. Whether you're upgrading your space for a fresh look or wondering how to repair a radiator, we've put together this handy step-by-step guide. We'll walk you through the replacement process and cover straightforward ways to handle a radiator repair.

Useful links

Match new pipe centres to existing pipework for a simple installation or ask a plumber to reposition the valves.
Isolate the water supply, drain trapped water with a key, swap the brackets, and secure the new radiator.
Tightening valves helps with a radiator leak repair, while bleeding the heating system quickly resolves cold spots.

Choosing the right radiator

There are a few things to consider when choosing a new radiator. When picking your new radiator, first consider the pipe centres. It's a good idea to select a replacement with pipe centres matching your existing pipework, and doing this can save you a lot of time. If this isn't possible, a plumber will need to reposition your valves.

You'll also need to check what your wall is made out of. For solid masonry, you can choose any size. If it's plasterboard, use a stud detector to find the wall supports to screw the brackets into. And if you can't align them, use wall plugs.

Next consider your radiator style and material. Horizontal radiators are the most common design, but if you’re working with a small space, a vertical radiator might be a better option. It’s also worth considering what your chosen radiator is made from as some materials (e.g. aluminium) heat up quicker than others, and some (e.g. mild steel) are more affordable than others. This way, you can find an option to suit your preferences and budget.

Lastly, you have the choice between single or double panel radiators, with double panel designed to provide 40-80% more heat output. In terms of aesthetics, column radiators provide a more traditional look, and flat panel radiators are more contemporary and minimalistic.

New radiator with valves and fixings
Adjustable wrench
Radiator key
Trays and towels (for water spillage)
PTFE tape

Replacing your radiator: a step-by-step guide

Turn off your heating via the boiler or thermostatic valve. Then you’ll need to isolate the radiator by closing each valve. Count the turns to switch them off, so you install the new one at the same flow rate.

Use a spanner to loosen the nut on the radiator valve, holding it tightly. Then, u se a radiator key to let trapped air out of the top, allowing water to flow. Place bowls underneath to catch any spills. Once water stops, remove the radiator, tip it sideways to release any remaining water and unscrew the brackets.

Fix the new brackets to the wall using the manufacturer's instructions, then carefully slide the new radiator onto them, making sure it's completely level and secure.

Wrap PTFE tape around each valve thread to create a seal and install the valves. Line up the radiator with your pipework and tighten the nuts. Fully open both valves to let water in, then open the lockshield valve by the turns you counted earlier.

Once installed, you'll need to bleed and rebalance it to ensure efficient heating. For more information on this step, check out our guides on how to bleed a radiator and how to balance a radiator.

Common home radiator problems and solutions

Sometimes you don't need a full replacement. If you're wondering how to fix a radiator leak, the answer depends on the source.

For a leaking valve, tightening the connection or adding fresh PTFE tape provides a reliable radiator leak repair.

For a radiator cold spots fix, bleeding trapped air restores heat.

If you’re wondering how to fix a faulty radiator thermostat valve, check out our handy guide on changing a TRV.

Once you’ve made these repairs, your floors will be dry and your heating will be working perfectly all winter long.

Radiator maintenance tips for homeowners

Once you’ve got your radiator working well, it’s important to keep up with its maintenance.

Bleed the radiator: once you’ve installed your new radiator, you’ll want to regularly bleed it as in Step 5 above. This will prevent air from becoming trapped in the system and stopping your radiators from heating up properly.

Flush the system: slush and debris can build up in your radiator over time, so flushing the system can flush this all out. This should however be done by a professional plumber.

Keep the radiator clear of furniture: if you’ve got furniture right in front of your radiator, this can affect how well their heat circulates around the room. You’ll want to keep any furniture at least 10cm away from your radiator to be able to feel its full heat in the room.

Check the thermostat: if your thermostat is faulty, this can affect how well your heating system heats up. It’s a good idea to keep checking the thermostat so you know your radiators are working to the best of their ability.

Upgrading your home heating doesn't have to be complicated. By following these steps, you'll ensure your space stays warm and comfortable. And if you're ever unsure, it's always best to ask a professional. Now you’ve installed your new radiator, take a look at our guide on how to get the most out of your heating system.

FAQs

To manage fixing a radiator leak at the valve, drain the water below the valve. Unscrew it, wrap PTFE tape around the olive, and tighten to create a watertight seal.

Small pinholes can sometimes be patched, but you generally cannot reliably repair a cracked radiator. If the metal has split, it's safer and more effective to replace the unit entirely.

Surface rust can be painted over. But if you're asking if a leaking radiator can be repaired when rust has caused a hole, the answer is no. Internal corrosion means it's time for a replacement.