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Radiator Valve Essential Guide: How to Know Exactly What to Buy

So, you've decided on a radiator. Now you just have to figure out which radiator valves you'll need. Which begs the question, why don't radiators just come with valves included?  

Actually, there’s a very good reason why your radiator doesn’t come with a pair of valves provided; and this guide will help you quickly understand which radiator valves you need and why.

Why Don't Radiators Come Supplied with Valves?

Radiators don't come with valves because it's better for you that they don't. You not only need to choose which radiator valves you want because your pipework isn't the same as everyone elses, but neither is your taste in interior decoration. You get to choose exactly which radiator valves match: your radiator, the angle/direction of your pipework and of course, your room's decor.

What does a radiator valve do?

Radiator valves control temperature, and they always come in pairs. One to adjust the amount of water entering the radiator to adjust temperature, and the other to balance your system by affecting the amount of heat exiting the radiator.

In basic terms, they're just like little taps for your radiator, and those taps are either referred to as manual or as thermostatic.

Manual and Thermostatic Valves, What's the Difference?

Manual Radiator Valves Explained

One of the easiest to use valve available, you just need to twist the top with your hand and it alters the flow of heat into your radiator - simple,  just like turning a tap.

They will tend to be simpler, and usually far smaller than thermostatic valves.

Let's take a look at some of our top picks below.


Thermostatic Radiator Valves (TRV) Explained

Thermostatic Valves, usually known as TRV valves feature a similar design to manual valves, except feature a sensor. While ‘sensor’ might sound electronic - and sure you can get electronic versions (even wifi thermostats) - TRV’s typically feature a more low tech design: a bit of wax or liquid, which reacts to room temperature and self-regulates the radiator within a certain limit. Basically, they can save you money when used right.

Just like with the manual valve, they’re always used in conjunction with a lockshield.

Let's have a look at some of our greatest hits when it comes to TRVs below.


Lockshield Valves Explained

Lockshield valves are supplied with your valve purchase. So when you buy a pair of valves, one of them will always be a lockshield.

Regardless of which radiator valves you choose - manual or thermostatic - the other end of your radiator will feature a lockshield valve. That's because it controls the flow of water leaving the radiator and is used to “balance” your system, which just means making sure that all of your radiators heat up at the same rate.

Whatever you choose, it's essential to make sure you find out if your valves need to be straight or angled.

Straight, Angled, Corner: Which Radiator Valves Fit Your Pipe Work?

Straight and Angled Valves Explained

Valves connect your pipes and radiator together, so both the placement and the design will have an impact as to which you will require:

Radiator Pipes coming out of wall Pipes coming out of floor Pipes run exposed along wall (rare)
Inlets on the side / side entry angled / corner angled angled
Inlets underneath / underside entry angled / corner straight angled


There can be a multitude of reasons why you might need straight or angled valves for you radiator. It is important to understand what you need and why.

Both the inlets on the radiator and the pipes which will connect to them should be really obvious to spot. But if not, call a plumber for advice. You might also want to consider a variation of the angled valve: the corner valve.


Corner Valves Explained

Corner valves (sometimes called flat front valves) are often a decorative choice, but angled thermostatic valves can protrude from your radiator a fair bit - becoming a painful magnet for bruised shins, hips, or even children's heads in the case of using a wall mounted rail.

So a corner valve is an angled valve whose top faces inwards, parallel with the wall, rather than outwards. It can make it more awkward to adjust, depending on the placement of your radiator, but the option is there.

Let's take a look at some of our top picks below.


What Size Radiator Valve Do I require?

While the overall size of each radiator valve can be dependant on the aesthetics and type (thermostatic valves are usually longer), we're going to talk about fitting sizes here. Meaning the width of the connections, measured in millimetres.

15mm valves are the only size you’re likely to encounter, since 15mm copper pipes are the most common. There are also other sizes, from 8mm to 28mm, and there are accompanying adapters. But for more information check out our in-depth radiator valve sizing guide.

Valve Styles: The Fun Stuff...

You’ve fallen in love with a radiator and had a good look at its inlets, and you’ve also checked your pipes, and perhaps you've also reached the stage where you've decided between manual or thermostatic. So now what?

Well you’ve still got choices to make, but now it’s just down to style!

Traditional, Minimalist, and Modern Valve Styles

Worried your vintage looking stainless steel radiator with hand-etched detailing will have to be sandwiched between two white plastic mushrooms? Not likely. Your real problem is deciding between the 4 pairs of Edwardian manual brass valves with similar etchings of their own...

Or maybe you want something else, whatever it is, there’s a perfect pair of valves out there for you.

Traditional Valves for Classic Homes

If you air on the traditional side of things, these designs are for you, take a look at some of our favourites and shop the full range below.


Modern Valves for Contemporary Homes

If you prefer to keep things a little more modern, then these might be more your style. Be sure to look at some of our best sellers below and then shop our full range too!



Now you understand why valves are sold separately to radiators and how to tell your thermostatic valve from your Manual. You also know how to choose the correct valve for the angle of your pipes and pick between the various styles available. Armed with this knowledge you're ready to go and purchase the perfect pair as the proverbial cherry atop your brand new radiator - or as a way to inject life into an old one.

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