How to Turn Off a Radiator UK

There are several practical reasons for turning off or reducing the heat from a radiator.

Whether you want to save energy in unused rooms or prepare for radiator replacement, it’s important to understand the correct process and key considerations.

In this guide, we’ll walk you through the steps to turn off or turn down a radiator and address some of the most frequently asked questions on the topic.

Why Turn a Radiator Down or Off?

There are a whole host of reasons why you might want to turn a radiator off (or simply lower it).

For example, if you are heading off on a holiday or otherwise will be leaving your property vacant for some time, you might want to lower or turn down the valves on your radiator to ensure you’re not wasting money on keeping an empty property warm while you’re away.

Alternatively, you might want to lower or turn off radiators in unused rooms.

While turning them off entirely may seem more sensible, there is a case to be made that simply lowering the valve on unused radiators will prove better for your pocket overall.

The Difference Between Isolating a Radiator and Turning It Off

It’s important to note that turning off a radiator by using the valve will not prevent the flow of hot water entirely.

However, if a radiator needs to be isolated then you need to take things up a notch by ensuring that you bring the flow of hot water to a halt.

However, please note that you should only undertake this sort of work if you have the right skills and knowledge. Otherwise, hire a qualified heating engineer or a certified plumber.

If, on the other hand, you’re looking to turn off the radiator, rather than isolate it, you must get this right.

After all, accidentally isolating a radiator may result in the radiator and pipework freezing over with the water inside expanding as it turns to ice.

These issues can cause pipes and the metal of the radiator to crack or rupture and fixing such problems would cost you a pretty penny.

Turning Off or Lowering a Radiator

Before we lay out the steps required to turn off your radiator or turn it down, it’s important that you know what type of valve your radiator features.

There are three primary types of radiator valves, namely, a thermostatic radiator valve or TRV, a lockshield valve and a manual valve.

Here is a summary of each type of radiator valve and how they differ:

Thermostatic Radiator Valve (TRV)

These modernised radiator valves come with built-in sensors allowing them to make automatic adjustments. Households with TRVs will also usually have a digital interface and temperature display on a smart thermostat.

Manual Valve

Manual valves can only be adjusted by physically turning them, which is one of the key differences between them and TRVs. 

Lockshield Valve

Lockshield valves are fundamentally different to TRVs and manual valves in that they are used to isolate radiators.

Both manual and TRVs are usually larger than lockshield valves and lockshield valves lack a number dial or an easy turn mechanism.

If you are unsure as to what type of valves you see on your radiator, you should either check with the manufacturer’s instructions or consult a professional.

Is your radiator leaking? It may be a lockshield valve leaking. 

How to Turn Off or Lower a Radiator with a TRV

If you’re sure that your radiator features a thermostatic radiator valve, here are the steps required to lower or turn off your radiator:

1. First, find the TRV. More than likely, it will be located on the left side of your radiator toward the bottom, although the exact location can vary depending on the radiator model in question. The TRV will also feature a number dial which will allow you to adjust how much your radiator will heat the room.

2. Turn the valve clockwise on the dial until it reaches ‘0’ or the equivalent setting for turning your radiator off. While turning off a radiator entirely would risk water inside the radiator and pipework freezing over, this is not a concern with TRVs due to their use of the frost prevention mode.

3. Of course, if you want to lower your radiator, you may want to switch it to a lower setting instead. We recommend double-checking the manufacturer’s instructions and following their advice as to what the ideal lower temperature should be and whether there are any caveats to the lowest setting of the TRV.

How to Turn Off or Lower a Radiator with a Manual Valve

Alternatively, if you’re certain your radiator uses a manual valve, you should take the following steps to lower or turn off your radiator:

1. Locate your radiator’s manual valve. You’ll find this valve on the bottom left or bottom right of your radiator.

2. To turn off your radiator, turn the valve clockwise until you reach the lowest setting. However, once you reach this position, be sure to turn it counterclockwise just a little. It’s important not to turn off radiator radiators with a manual valve completely as this can result in the water inside your radiator and the return pipes freezing over, which in turn could cause pipes and parts of the radiator to rupture. Unlike TRVs, manual valves do not feature a built-in frost protection mode.

3. If you’d prefer to lower it, simply adjust the valve dial to a slightly lower setting. Be sure to verify with the manufacturer’s instructions as to what lower temperature is sufficient (if, for instance, you wish to lower a radiator in an unused room) and whether there are any caveats when it comes to turning off your radiator.

How do I isolate a radiator?

The exact steps required to isolate a radiator will depend on whether you want to isolate a radiator with a TRV or manual valve.

Either way, you should follow the manufacturer’s instructions to a T to ensure you do not make any mistakes along the way.

Also, as mentioned earlier, if you wish to isolate a radiator for a specific task (e.g., removing a radiator ahead of decorative work), be sure that you know exactly what is involved. If in doubt, always give a professional a shout.

Can I have the manual valves of my radiators replaced with modern TRVs? And, if so, how much might this cost?

Whether or not you’ll be able to swap out your manual valves for TRVs will depend on the type of radiator you have.

Sometimes, it will be possible, but in other cases, you’d have to have entirely new radiators installed to benefit from thermostatic radiator valves. 

If you’re unsure, it’s best to contact the manufacturer directly or call out a professional to take a look and make an assessment 

As for the cost, it will likely set you back about £10 to £30 per TRV in supply costs.

Obviously, the total cost (which must also factor in the price of labour) will depend on how many radiators you wish to have TRVs added to.

In the case of 9-10 radiators, the price estimate rises from £120 to £420.

For properties with 11-15 radiators, expect a bill of somewhere between £140 and £630.

Lastly, if you have a large home with around 16+ radiators, you might end up paying as little as just over £200 or you may end up potentially paying in excess of £800.

How long do TRVs tend to last?

The longevity of a thermostatic radiator valve will depend on the quality of the product and how well it is maintained, but as a rule of thumb, a TRV will usually need replacing after ten years.

If your TRV has been going for a decade or longer, it would be best to have it replaced rather than push your luck as TRVs can see a rapid decline in performance once they reach a certain age.