Radiator Valves Explained

Last updated: June 8, 2021

Installing new radiators in your home can greatly improve the energy efficiency of your central heating system and even help you save on bills. But did you know that how efficiently your new radiators will perform greatly depends on the radiator valves you install?

Radiators don’t come with valves provided because there is no universal solution; every home has different pipework and every family has different needs and preferences, so it’s better that they don’t come included. This way, you have the freedom to choose the valves you think are best suited to your needs and budget. To help you choose the right valves for your radiators, we explore in detail all types available on the market, including manual, thermostatic and intelligent valves.

What Does a Radiator Valve Do?

Radiator valves control the heat that your radiators give out. They come in pairs: the job of the first valve (known as the wheelhead valve) is to control the flow of water, or to be more precise, to determine just how much water enters the radiator and its counterpart; valve number 2 controls exactly how much heat the radiator will emit.

Valve number 2 is often referred to as the “lockshield” valve. These lockshield valves are usually covered in a plastic cap and control the total amount of heat that the radiator emits at a given time.

These pairs are either manual valves or thermostatic radiator valves (TRVs) if we’re using the technical industry lingo. TRV’s are self-regulating devices and can quickly change the room temperature by shifting the flow of hot water to the particular radiator and shutting down when the desired level is reached. While a thermostat is usually responsible for controlling the overall heating supply in an entire house or building, the valves connect to a specific radiator and form an integral part of any central heating system. For this reason, these valves can specify which radiators get heat. For example, if the entire family is downstairs, you might not want to use extra electricity and keep the bedroom radiators on.

Radiator valves thus allow you to change the heat as needed and, in this way, can save your energy consumption and electrical bills. As mentioned they are not included when you purchase a new radiator, and this is because they aren’t one-size-fits-all devices. Different valves will suit different people and their particular needs.

Manual and Thermostatic Valves: What’s the Difference?

There are two main types of radiator valves on the market, namely manual and thermostatic ones. More and more, however, we are seeing an increase in intelligent valves. These are particularly innovative as they allow you to control your central heating system via an app on your smartphone, but more on these ones later!

Manual Valves Explained

A manual valve is an original design. True to their name, they are manually operated and can be turned on, off, up, or down. When you turn the valve up or down, you change the amount of hot water entering the radiator. The more hot water that enters your radiator, the toastier the room will be.

Manual models are the simplest and easiest models on the block and are super easy to navigate. However, since they have to be turned on and off manually and each radiator needs to be adjusted manually, they can be a bit time-consuming.

Moreover, if you forget to turn down a particular valve when you go out, you could rack up those energy costs.

Thermostatic Valves Explained

Next up, we have thermostatic radiator valves. These are a little more complex than the manual models but not quite as advanced as smart valves. TRVs give consumers superior control over their homes.

Rather than rolling the valve up or down as you would with a manual device, you can set a particular temperature on the valve, and this will then heat your home accordingly. The TRVs come in two designs: wax or liquid. Both models are great but the liquid one is a more recent development, so it’s able to provide quicker adjustment according to room temperature changes.

Once it reaches the desired degree, the TRV will automatically switch off and ensure that no more hot water enters your heating system. As such, these radiators are able to mostly self-regulate. This can save you time and a great deal of money in the long run since they automatically shut off when the chosen level has been reached. If you want to save on heating bills, this radiator valve might be your best bet.

Smart Radiator Valves Explained

The most comprehensive and innovative type of valve is a smart valve. Since they work with smart thermostats and can connect to Wi-Fi, smart radiator valves can be controlled via an app on your mobile phone and used from anywhere in the world. This means that you can set the radiator from home or from the office if you know it’s going to be a chilly evening, and you can even switch your radiator off when you’re not at home if you forget.

Naturally, these systems are more expensive than manual and thermostatic valves, but their benefits are remarkable. They’re an excellent choice for anyone wanting to upgrade to an intelligent home.

Home central heating system

What Do the Numbers on a Radiator Valve Mean?

Now that we’ve covered the differences between manual, thermostatic and smart valves, it’s time we talk about the valve numbers and what they really mean. Radiator valves are usually numbered from 1-6, and each number correlates to a rough temperature in the room.

Since radiator manufacturers cannot guarantee the exact temperature in your room (as there are many factors that can affect it), they’ve chosen a number system rather than specific temperatures. As a rule of thumb, level 3 should generally work around 20°C. Each time you turn the dial-up and down, you’ll create a difference of about four degrees. So, a level 2 will be about 16 degrees, and a level 4 will be around 24 degrees.

As you become familiar with your radiator and its number settings, you’ll be able to find your comfortable temperature. While some people might enjoy a piping hot living room, others might prefer a slightly cooler temperature. Bear in mind that by turning down your radiator valve one notch, you can save a great deal of power, with researchers estimating up to 6%.

TRV’s – A Word to the wise 

If you are opting for a thermostatic valve, you will need to remember that it senses the surrounding temperatures. For this reason, it’s often advised that individuals use manual models in bathrooms. TRVs might mistake the hot steam for hotter temperatures and subsequently turn off, leaving you all too chilly when you step out of the shower.

As such, if you have a heated towel rail, a manual or intelligent device might be your best bet. Be sure to also keep them away from areas and rooms with a wall-mounted TRV as these might both try to control the specific temperature of the radiator, and this could cause some problems.

Straight, Angled, Corner valves, or H-Block Valves?

Whether you opt for a manual model, a TRV, or a smart device, the shape of the valves is of great importance. When it comes to the forms, you can choose between straight radiator valves, corner radiator valves, angled radiator valves, and h block valves.

Basically, different shapes exist to ensure compatibility between the positioning of the radiator and the valves. Let’s explore them in detail.

Straight Radiator Valve:

These straight valves, true to their name, are straight and without any bends. Water will thus flow up the radiator from the floor or across a wall.

Angled Radiator Valve: 

Angled radiator models are the most common type of radiator valves in Britain, with around 90% of homes having them. They are a great option as they can bend with piping. You’ll notice this type as they pop out at the bottom of radiators.

Corner Radiator valve: 

Corner models are an excellent choice if you are living in a small apartment or a restricted space. However, since they face the wall, it can be a little hard to manage radiator control as you might struggle a bit to turn the radiator knob.

H-Block Radiator Valve:

These knobs are installed in the middle of your radiator and an excellent pick for saving space and effectively turning the dial.

What Size of Radiator Valve Do I Require?

First things first: what do we mean when we talk about the size of the radiator valves?

You might be surprised to learn that the size of the valve refers to the pipes and connections and not the overall size of the valve itself. With this in mind, pipes are usually about 15mm, so radiator valves are designed to fit this size. However, there it’s not that uncommon to have pipes between 8mm and 28mm as well. If your pipework is bigger or smaller than the standard 15mm and you can’t find the valves in the right size, we suggest purchasing adapters.

How Much Do They Cost?

Manual valves are the cheapest and can be sold from anywhere between 5 pounds and 30 pounds. Next up are the thermostatic models which can sell from 5 pounds to over 100 pounds, depending on the mode.

Finally, the smart valves are most expensive and are between 50 pounds to a couple of hundred pounds. However, you should factor in the additional charge of the intelligent thermostat.

Conclusion – Radiator Valves Explained

Whether you opt for manual radiator valves, TRVs, or smart devices, knowledge is power. Once you understand how they work, you can choose the best option for your needs and preferences.

Whatever type of radiator or radiator valve you choose, opt for a reputable team to do the job.

You may also like our comprehensive review of the Best Radiator Paint.