How smart radiator valves work

Smart radiator valves, sometimes called smart radiator thermostats, take your smart home heating to the next level.

They can be programmed and controlled remotely through your smartphone, meaning you can set the temperature of individual rooms. Pair them up with a smart thermostat and you can set up a heating schedule that runs completely by itself.

Manufacturers promise big savings on your heating bills, and, if used well, they are a more sustainable method of heating your house.

This guide breaks down everything you need to know so you can decide if there is a place in your home for smart radiator valves.

Smart radiator valve reviews – find the ones that aced our testing

How do smart radiator valves work?

Many homes already have thermostatic radiator valves (or TRVs for short) on their radiators.

They work by detecting the temperature of the room the radiator is in, and turn the radiator on or off depending on whether the room needs heating up or not. 

TRVs uses a 0-5 scale – with 0 turning the radiator completely off. You set the temperature by twisting the body of the valve.

Having TRVs installed on your radiators allows you to set the temperature in individual rooms. This makes it easier for you to keep rooms at a consistent and comfortable temperature and save on heating bills by only heating the rooms you need to.

The function of a smart radiator valve (or SRV for short) is exactly the same, but with these four key advantages: 

1. You can control a smart radiator valve remotely through a smartphone app.
2. You can set heating schedules with smart radiator valves through a smartphone app.
3. You can set the temperature of a smart radiator valve in degrees celsius.
4. Some have further energy-saving smart features, such as 'open window detection' that turns the radiator off if you open a window in the room.

Installing and connecting smart radiator valves

Unlike a smart thermostat, you can install a SRV without needing the help of a professional. In most cases, you simply:

• remove the old TRV from your radiator 
• put the correct adaptor on the valve (most smart radiator valves come with adaptors for the most common valves) 
• put the batteries into your new SRV
• and attach the SRV to your radiator.

In order to use a manufacturer's smart radiator valve, you will need the manufacturer's connecting device. It's often called a bridge, or gateway. 

This connecting device plugs into your broadband modem and allows your smart heating appliances to be controlled by your smartphone app. 

If you already have a smart thermostat, you've more than likely got that manufacturer's connecting device already. If you're just starting out with smart heating, most manufacturers sell starter packs that include the connecting device, smart thermostat and/or smart radiator valves.

Most smart radiator valves only work with their manufacturer's smart thermostat and connecting device. So if you're buying 'off brand' it's worth checking its compatibility with any existing home heating setup you have.

How we test smart radiator valves – learn how we sort the best from the worst.

Different smart home heating setups 

Below are the three simplest heating setups. We show you what you can and can't do with them.

Thermostat and thermostatic radiator valves

This is the set up a lot of homes will have. You can manually set the thermostat temperature, and it will turn the boiler on and off to maintain the temperature of the room it's placed in.

You can also set the temperature of each room using the thermostatic radiator valves. In the diagram below:

• Bedroom 1 is set to 5 (approximately 25-30°C)
• Office to 3 (approximately 15-20°C)
• Bedroom 2 to 0 (radiator off).

You would have to go to each room to manually change this. Because the valves can't communicate with the thermostat, the radiators will only heat up if the boiler is already turned on.

What you can do:

• use the thermostat to turn the boiler on and off
• control the temperature of individual rooms with thermostatic radiator valves.

What you can't do:

• control the thermostat or thermostatic radiator valves remotely from, say, your phone
• turn the boiler on or off by changing the setting of a radiator valve
• easily create zoned heating for different times of the day (if you are willing to go and adjust the radiator valves by hand at different times of the day, every day, then technically you can. But it is a lot of effort).

Smart thermostat and thermostatic radiator valves

As shown by the dotted line in the diagram below, you can use your smartphone to communicate wirelessly with your smart thermostat via a compatible connecting device.

This means you can remotely set the thermostat temperature, and it will turn the boiler on and off to maintain the temperature of the room it's placed in. 

You can also set up heating schedules within the app to change the thermostat temperature throughout the day. In the diagram above, the thermostat is located in the living room. So you could set it to 18°C and also schedule this to change to 20°C between 7pm - 8pm, making it nice and cosy for you in the evening when you settle down in front of the TV.

You can set the temperature of each room using the thermostatic radiator valves. However, as seen on the diagram, the valves can't communicate with the smart thermostat or your smartphone, so you will have to change them manually.

What you can do:

• control your smart thermostat remotely with your smartphone
• use the smart thermostat to remotely turn your boiler on and off
• program heating schedules with your smartphone.

What you cannot do:

• control the thermostatic radiator valves remotely
• turn the boiler on or off by changing the setting of a radiator valve
• easily create zoned heating for different times of the day.

Smart thermostat with smart radiator valves

As shown by the dotted line in the diagram below, you can use your smartphone to communicate wirelessly with your smart thermostat and also the smart radiator valves, via a compatible connecting device.

This means you can remotely set the thermostat and smart radiator valves temperatures. You can even set the exact temperature with smart radiator valves, instead of the 'rough' temperature as you do with thermostatic radiator valves.

All the smart radiator valves can communicate with the smart thermostat, meaning you can turn the boiler on and off by changing the settings of any of the heating devices. Out of our three home setups, this gives you the most complete control of your heating.

You can easily set up heating schedules. For example, the heating can be turned off in all the rooms but the office during the day, and then be turned on low in the bedrooms and higher in the living room during the evening. 

This allows you to only have heating on when you need it, and in the rooms you need it – potentially saving money on heating bills.

What you can do:

• control your smart thermostat and smart radiator valve settings remotely with your smartphone
• turn the boiler on or off remotely with the smart thermostat or changing the setting of a radiator valve
• program heating schedules with your smartphone
• easily create zoned heating for different times of the day.

What you can't do:

• In theory you can control every aspect of your home heating, but this setup is the most complex. It can be tricky to use to its full potential if you are not tech savvy.

Best Buy smart thermostats – find a top thermostat to start your journey to smart home heating.

Are smart radiator valves worth it?

Ultimately, it depends what you want smart heating for to decide if it's worth getting. Smart radiator valves offer high levels of control, but that doesn't suit everyone.

Smart radiator valve pros

• You set the temperature in degrees celsius This is easier to use and more intuitive than the 0-5 scale on TRVs.
• You can change the settings remotely You don't have to go round your whole home changing each valve's settings, if you want to heat rooms differently.
• You can see how much you're heating Many smart heating apps allow you to monitor your energy use, making it easier to see where you could be saving money.
• You can create zoned heating If you want smart heating where you can control the temperature and whether the heating is on or off in each room, smart radiator valves allow you to do this.

Smart radiator valve cons

• Price Smart radiator valves typically cost between £35 and £80 each, about five times more than a traditional TRV. That cost adds up if you want smart valves on multiple radiators.
• Limited functionality without a smart thermostat You need a compatible smart thermostat if you want to get everything that a smart radiator valve has to offer, as this will allow your valves to communicate with the boiler to turn it on and off.
• You're locked into a brand Most smart radiator valves are only compatible with that manufacturer's smart thermostat and connecting device. This means you'll more than likely have to buy into one brand's ecosystem if you're upgrading. If you already have a smart thermostat, you'll most likely have to get that company's smart radiator valves.

Smart radiator valves are great if you want complete control and transparency over how much you're using your heating. 

If you have a regular schedule, you may well benefit from being able to program a heating schedule. 

Conversely, if you go away on holiday – or just a night out – you can easily turn the heating off to save money, then turn it back on when you're on your way back so you're greeted to a nice warm home.

However, if you don't own a smartphone or don't like using one, you're unlikely to get the full benefit out of a smart radiator valve. 

Small spaces, such as a one-bed flat or bedsit, tend to only have one or two radiators. So buying smart radiator valves for such homes won't be of much benefit.

Do smart radiator valves save you money?

Yes, but probably not as much as manufacturers claim. If your home is poorly insulated, you'll make greater savings on your energy bills by improving your home insulation first. Smart heating can then shave off a few more pennies.

Most estimates on savings that can be made with smart home heating assume that, before you started using smart heating, you left your heating set to maintain a constant temperature during the day.

So if you already turn your heating off when you leave home, or don't have it on for long periods of the day, you're unlikely to save as much as the manufacturers claim. 

Having said this, smart radiator valves allow for greater control than just a smart thermostat on its own – so having both and using them wisely will gift you more savings than if you just have a smart thermostat.

Are smart thermostats worth it? – we break down the costs to see how much you actually save

Wi-fi and smart radiator valves: what's the difference?

Wi-fi (or wireless) radiator valves and smart radiator valves are not the same thing.

• Wi-fi radiator valves cannot communicate with a smart thermostat (so they cannot turn your boiler on and off).
• They can let you change their temperature remotely using a smartphone app.

Essentially, a wi-fi radiator valve is just a traditional TRV that you can adjust remotely. 

This can be a good thing depending on what you're after. You don't need to purchase a smart thermostat or connecting device to start using a wi-fi radiator valve, meaning they're less of an upfront cost. If you want to dip your toes into the world of smart heating for the first time, wi-fi radiator valves could be an ideal first step.

However, you won't get the 'smarter' functions or complete heating control that's possible with a smart thermostat and smart radiator valve setup.

It's also worth noting here that you can use smart radiator valves without a smart thermostat, but this setup would have the same limitations of wi-fi radiator valves.

Nest vs other smart thermostats - is the extra cost worth it?

Smart radiator valves compatible with Alexa

• Drayton Wiser Smart Heating Radiator Thermostat
• Energenie MiHome Smart Radiator Valve Kit
• Hive Radiator Valve
• Honeywell Home Evohome Radiator Zone Kit
• Netatmo Smart Radiator Valve Starter Pack
• Salus Single Zone Smart Home Starter Pack
• Tado Smart Radiator Thermostat
• Worcester Bosch Easycontrol Smart TRV

How to buy the best smart thermostat – what are the features to look out for?

Smart radiators valves without a hub

Most smart radiator valves require a hub to communicate with your smart thermostat and your smartphone app. 

If you don’t want a hub, there are options out there (like wi-fi radiator valves), but be aware that this comes with less functionality. So you won’t be able to communicate with your thermostat to bring the boiler on and off.

Manufacturers such as Radbot have radiator valves that detect when a person is in a room and only heats it whilst they are in the room. It doesn’t use wi-fi or a smartphone app, so it's potentially a great solution if you're less tech savvy and want a bit of automation to your home heating.