A Thermostatic Radiator Valve often referred to as a (TRV) is a valve that controls the flow of water in a central heating system. It is fitted to the radiator and uses a built-in sensor to monitor the air temperature around the radiator.

The valve head is usually marked with a temperature scale that allows you to set the required heat output from the radiator.

How Do Thermostats On Radiators (TRV) Work?

As the air temperature around the radiator changes, the TRV senses this and adjusts the flow of water accordingly.

If the room gets warmer, the TRV will close slightly to reduce the flow of water and therefore the heat output from the radiator. Conversely, if the room gets cooler, the TRV will open slightly to increase the flow of water and heat output.

TRVs can be used in conjunction with thermostats to provide greater control over your heating system.

For example, you could use a thermostat to control when your heating comes on and then use TRVs to control how much heat each individual radiator puts out.

If you have a room that is particularly cold or if you find that your radiator is not coming on as often as you would like, then you may benefit from fitting a TRV. TRVs can also help to reduce your energy bills by ensuring that heat is only being generated when and where it is needed.

Thermostatic Radiator Valves are an energy-efficient way to heat your home as they only use the amount of energy needed to maintain the desired temperature, rather than heating a room to a set temperature and then letting the heat escape.

How Much Does A Thermostatic Radiator Valve Cost?

A standard pair of TRVs cost around £20 on average. However, the cost will vary depending on the brand, style, and features of the TRV.

You can either get liquid-filled or wax-filled radiator valves. Wax-filled radiator valves tend to be more expensive than liquid-filled radiator valves, but they are also more durable and have a longer lifespan.

Are Thermostatic Radiator Valves Worth It?

Yes, 100%. Since you have the ability to adjust the temperature in different rooms, you have the potential to save a lot of money on your energy bills. TRVs also help to reduce your carbon footprint as they only use the energy needed to maintain the desired temperature.

With half the energy in your home being used to either heat your home or hot water, by combining a TRV with heating controls, you have the potential to save a lot of money annually on your energy bills.

A TRV is a great investment for your home and one that will quickly pay for itself in savings. Not only will you save money, but you’ll also be doing your bit to help the environment by using less energy.

Can I Install A TRV In Every Room?

Even though you can fit a TRV in every room, there’s really no need to fit one in a room that has a fixed thermostat like your living room. In fact, it’s a waste of money as the thermostat will take precedence over the TRV and your radiator will be either on or off regardless of the TRV setting.

It’s also worth noting that some rooms like the kitchen or bathroom may get too hot with a TRV fitted so you’ll need to be careful when deciding which rooms to install them in.

If you’re unsure whether or not a TRV is right for your home, then we recommend talking to a heating engineer who will be able to advise you on the best way to improve your heating system.

What Do The Numbers On Radiator Valves Mean?

A lot of people assume that the numbers on your TRV represent the temperature in the room, but this is not the case. The numbers actually represent the percentage of open/closed that the valve is.

For example, if your TRV is on setting “5”, then it means that the valve is 5% open and 95% closed. This will allow a small amount of heat to flow through the radiator which is perfect for when you don’t need the room to be too warm.

Conversely, if your TRV is on setting “10”, then it means that the valve is 10% open and 90% closed. This will allow more heat to flow through the radiator which is perfect for when you need the room to be warmer.

It’s also worth noting that most TRVs have a minimum and maximum setting.

How Often Should I Replace My Thermostatic Radiator Valve?

You should replace your TRV every 5-10 years, depending on the brand and quality of the valve. It is also a good idea to check your TRVs regularly for any signs of wear and tear such as leaks, cracks, or damage to the valve head.

Oftentimes, if you have old TRVs that are stiff or hard to turn, a squirt of WD40 can help to loosen them up.

Thermostatic Radiator Valves Settings

Most standards recommend heating your house to 70 degrees Fahrenheit (21 degrees Celsius) and bedrooms should be kept a few cooler at around 64 degrees Fahrenheit (18 degrees Celsius). For most people, this temperature will be pleasant, but if it’s too warm (or rather chilly) for your liking, you can always adjust the settings on your TRV.


Why does one radiator not have a thermostat?

It is typical practice to leave one thermostatic radiator valve off and to have the appliance continually switched on. If your boiler has a flow meter, which tells when all of your radiator valves are closed, you may install a TRV on each radiator if you like?

What side of the radiator is the thermostatic valve?

The majority of thermostatic radiator valves are bi-directional, so they may be used on either the supply or return pipes of your radiator. It’s always preferable to install the TRV on the flow pipe that leads into your radiator, though.

Are all radiator valves the same size?

Modern radiators and valves employ the same connection between your valve and the radiator. The width of your pipes that the valves will fit onto is referred to as “diameter.” It’s generally 15mm, but you can verify this by measuring your pipes.

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