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Smart Boilers: What is a smart boiler and how do they work?

What is a smart boiler?

Technology has reached into just about every area of our lives, and now our central heating and hot water controls have moved into the 21st century.

Now your boiler can be controlled via your mobile phone simply through the addition of a smart thermostat. That’s all it needs to then be considered a smart boiler.

Wondering what exactly a smart thermostat is? Well, this guide has all answers for you!

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What is a smart thermostat?

phone controlled temperature

So, you might think that the ‘smart’ part of the smart thermostat refers to how clever it is. Well, they are clever, but smart actually stands for Self-Monitoring Analysis & Reporting Technology.

The smart thermostat is controlled via an app on your phone or tablet. That then means that as long as you have an internet connection, then you have complete control over your heating system.

Wondering how does a smart thermostat connect to a boiler? Well, there are actually three different components to the smart device.

1. Smart boiler connection

This first component plugs directly into the boiler. It can then talk wirelessly to the second component

2. Control unit

This is the main control unit which is also the thermostat and controls what’s happening with the home heating system.

3. Mobile application

The final element is the smartphone app that you’ll need to download onto your smartphone or tablet. This is what then provides homeowners with control of their central heating systems no matter where they are.

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Features of smart thermostats

The features offered by a smart thermostat do vary between the different makes. However, here are some of the key functions you’re likely to find.

Multi-room thermostatic controls

Most people like different rooms to be set to different temperatures. You might like the bedroom to be quite cool so that you can snuggle under the duvet. But when you’re in the living room watching TV, you want to be nice and warm.


With a smart heating system, you can set different temperatures for each room in the house. The only additional requirement is to have smart thermostatic radiator valves in each of the rooms that you’d like individual control over.

That’s because this is what then connects with the app and allows you to have independent control over the heating.

So, you do need to consider how important this feature is. If you’re unlikely to need the ability to change settings for each room, then there’s no opportunity for energy savings, and so this functionality won’t save you money, especially when you factor in the cost of the radiator valves.

Smart learning thermostat

Some manufacturers, such as Google, with their nest learning thermostat, claim that their products have the ability to learn your heating habits. This includes the times that you tend to put the heating on and how high you have the thermostat set.

Then with this knowledge of your heating patterns, the smart thermostat will set the heating to your desired temperature before you’ve even thought about it.

Now, this definitely has the potential to save you time. Though it does assume that you are a huge creature of habit and like the smart heating to adjust itself to that routine.

However, if your life is a little less predictable, then you have losing control over the central heating, and this could result in an increase in energy use and heating bills.

This type of prediction of your heating can be switched off. So, if you’re finding that your lifestyle doesn’t fit with these type of smart heating systems, you can disable this function and still enjoy the other benefits.  

Weather responsive

You might be wondering what’s new about this, as many heating systems already have what might seem to be a very similar functionality. You might know this as an ‘outdoor reset control’.

This uses a sensor that is mounted on the north side of your home. This then communicates with another sensor that’s been connected to your boiler.

Know that the system knows what the weather conditions are outside, it can balance your water temperature with the outdoor temperature.

Smart thermostats take things one step further. Rather than relying on a temperature reading, they take information from other sources as well, such as the weather forecast.

Then, using complex algorithms, it can then consider factors such as residual heat. That, in turn, means the opportunity to save energy.

What we really love about this function is that you can make sure that your home is always at the perfect temperature no matter what the weather conditions are outside.

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Motions sensors and GPS tracking

GPS tracking

Some smart thermostats, including the tado° system, feature what’s called geolocation tracking. This means that it can consider where you are in order to decide whether to turn your heating on or adjust the temperature up or down.

Viessmann 050-W combi boiler

The smart thermostat knows what your preferred heating setting is and so as you arrive home, it makes adjustments to the heating level.

This is a perfect solution for someone who doesn’t have a fixed routine. A traditional thermostat would mean that the heating would come on at a predetermined time but if you arrive home at different times then you could be wasting energy and heating an empty home.

The one downside to this type of system is that everyone in the home needs to have the app. That way no one is sat at home freezing cold because the system doesn’t recognise that anyone is there. However, that can be solved with the next functionality, motion sensors.

Motion sensors

The Hive Motion Sensor uses infrared technology to detect movement around your home.

Now while that’s a great tool for security as it sends alerts via the mobile app, it can also provide information to the smart thermostat. No one in the room? Then the heating can be turned off in that location.

What’s really nice about this product is that you don’t need to call a technician or British gas engineers to install it.

All you have to do is to place the sensor on a surface or fix it to the wall. Then it can be activated and connected with the Hive system through the mobile app.

Never again will you go out and then remember that you’ve left the heating on!

Open window alert!

save money

How cool would it be if your smart thermostat alerted you to the fact that the home heating is on and a window is open? Tado°’s Open Window Detection does just that to prevent all the warm air from going out of the window and so helps you to save money.

Wondering what smart technology is being used to know if a window is open?

Well, it uses sudden changes in temperature or humidity and if it decides that a window is open, then it switches off for a while to save energy. By default, the tado° switches off for 15 minutes after an open window is detected, though it’s easy to adjust this in-app if you need to.

You do need to keep in mind that your smart thermostat won’t be able to provide this alert if the heating is set off. So, useful to make sure that you’re not heating necessarily but it’s not designed as a fail-proof security system.

Disadvantages of a smart boiler


Although smart boilers do have a lot of useful features, there are some potential cons that they have, depending on the person who has the boiler. These disadvantages can include:

  • Some technology may only work with the same brand of boiler
  • Some might only be compatible with newer boilers
  • Smart boilers try to learn your routine. If this is inconsistent, it may not be able to do all the features you require it.

Of course, the pros of smart boilers and thermostats outway the cons by quite a bit, with these points only being small concerns when considering a smart boiler. However, make sure you take these into account if you are wanting to make the investment, as these could apply to you.

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How is a smart thermostat different to a standard one?

Most homes have some type of programmable thermostat. However, that doesn’t mean to say that it’s the best smart thermostat for your home.

With a standard thermostat, you simply enter your home’s heating schedule that fits with the times that you need the heating on.

That might be on for an hour when you up in the morning and then on again for when you get home for work. But there’s no way to adjust that unless you physically go to where the thermostat is and make the required change.

When we then consider smart boilers, well, they are so much smarter than a programmable thermostat. It can actually learn your routines and then predict when you’ll want the heating on based on outside temperatures. And best of all, if you’re going to be out longer than expected it’s easy to adjust the schedule through the app.

Headed away for the weekend and realised you’ve left the heating on? No problem log onto the app and turn it off! (Though the smartest of the smart thermostats will know that no one is in and turn the heating off for you before you even knew it was still on!)

Is a smart thermostat the same as a smart meter?

They sound very similar but smart thermostats are very different to a smart meters.

As we’ve already discussed, smart thermostats provide a range of different functions to give you much greater control of your heating system even when you’re away from home.

hive active heating

Smart meters are mainly there to take readings of your gas and electricity use.

Smart meters are being offered to all homes throughout England, Scotland and Wales.

However, if you don’t want one, you don’t have to have one fitted. The smart meter takes automatic meter readings and then sends that information to your supplier. This, in turn, means the end of estimated energy bills.

The smart meter can also provide you with more detailed information on your energy use through an in-house display.

However, that’s where their functions come to an end; you’re not going to get the heating controls that come with smart thermostats.

Can a smart thermostat work with my heating?

Smart thermostats work with most boiler types including system boilers.

That also includes different types of fuel, so that’s standard gas boilers and electric boilers. There are also options for oil boilers so it is likely that your boiler will be compatible.

Essentially, if your system can be controlled by a standard thermostat or programmer, then it should be compatible with a new smart thermostat.

If you have a communal or district system for your heating then most smart thermostats will still work as long as you use an individual thermostat. Unfortunately, if you have storage heaters or a heat pump then you’re probably not going to find compatible smart heating controls.

Most manufacturers of smart thermostats list which boilers their products are compatible with.

So, it’s worth checking that before making a purchase of your new boiler or smart thermostat. Here’s the compatibility pages for the three most popular smart thermostats – HiveNest and Tado.

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Can hot water be controlled by smart boilers?

Some smart thermostats can also make your boiler smart so that means that you can also control your hot water through the app.

hot water

However, this is only applicable if you have a system or regular heating system. So even if you have the best combi boiler, you may not be able to control it through the smart system.

So once your boiler smart functionality is enabled then you’ll be able to switch the hot water off when you go on holiday, then on the way back home you can switch it back on again just by using the app.

Depending on the make of your boiler, you may need additional parts to be installed before it’s up and running.

What are my options for smart heating controls?

We’ve taken a look at three of the best-known options, Hive, Nest and Tado but there are other smart thermostats available.

Some manufacturers such as Worcester boilers and Vaillant boilers have either their own smart system or make recommendations for the most suitable option for a new boiler quote.


Hive launched in 2013 and is part of British Gas. Although there were some criticisms of their first edition, the second version has had fantastic reviews.

This smart thermostat provides historical information on temperatures both inside and outside of your home which make sit easy for you to see where money could be saved in the future.

The features you can expect to see with Hive smart heating controls include:

  • multi zone functionality
  • hot water control
  • geolocation
  • notifications on temperature notifications
  • weather forecasts, frost protection and holiday mode.


The Nest is one of the best known smart thermostats and that should be no surprise really as it comes from the tech powerhouse, Google.

If you want to integrate your heating controls and hot water supply into Google Home, then this is the Nest thermostat can to do that for you.

If you’re not familiar with Google home, well, this is the ultimate way for smart homes to be connected.

nest thermostat

A smart-hub device connects all the smart devices in your home so not only can it help you with energy usage and saving money, but it can also turn on the lights, play your favourite music and provide the latest news!

Nest can help you to keep your home at an energy-efficient temperature and save you money.


Tado is a German smart heating thermostat and one of the only smart thermostats that offer an Energy Saving Guarantee.

They guarantee that you’ll save more money with tado° than you did without it. And if you’re not satisfied or don’t feel that you’ve saved enough, then you can claim your money back!

We really like the geofencing functionality on this device. This active heating functionality links all the smartphones of everyone that lives in the home.

That then means that it knows when everyone is out and the heating needs to go off, or if one person is home and it needs to stay on. It’s even possible for each user to have their own heating preferences for the ultimate in smart homes control.

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Who will save money with a smart thermostat?

While it might seem as if a smart thermostat is right for every home, that’s not always the case. We’ve taken a closer look at what type go homeowner is likely to make the best use of the system and make the biggest savings.

If you are thinking about smart thermostats as a way to save money, then you’ve got the best chance of achieving that goal if you fit into one of the following categories:

If you love tech


If you always have a smartphone on you and you have a whole range of apps that you use on a regular basis then smart heating controls are likely to be right up your street.

After all to use things like remote control you’re going to need a mobile device to do that from.

Setting up a smart boiler installation isn’t complicated but you do need to be comfortable with using technology.

If you’re sure you’d like a smart thermostat but you’re not so sure about how to use it, we recommend taking the professional installation package.

That way it’ll be up and running before the engineer leaves and they’ll be able to show you how to use the key functions.

If you like detail

If you check your electric bill each month to work out where the expense has come from and you often change energy provider to get the best boiler deals, then again smart thermostats could be a good fit.

That’s because you’ll be able to carefully monitor your energy usage via a smart device giving you greater control of your spending.

Want to know the impact of turning up the heating? You can have that information immediately.

Great for busy people

If life is always chaotic and you’re running out of the door each morning, then having a smart boiler gives you one less thing to think about.

That’s because you don’t even need to remember to turn the heat off before you leave, that’s because, with smart heating, it’ll recognise you’ve gone out and adjusted the temperature automatically.

If you fit into this category, then you should have a look at smart learning thermostats. These devices will soon learn your routines along with your likes and dislikes.

Once it has that knowledge then it’ll run your system for you without you needing to do another thing.

People with a regular routine

We just mentioned about learning thermostats and smart devices such as the Nest learning thermostat work best when there is a regular routine.

That’s because regular use of the system in a particular way allows the thermostat to learn your preferences.

Once it has that knowledge, then it can ensure that the heating is at the right setting at the appropriate time.

If there is no stability in the way in which you use the heating, then it’s virtually impossible for the smart thermostat to be able to predict your requirements with any accuracy.

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Who may not save money with a smart thermostat?

Someone who is planning to move house

new home

If you’re going to be in your home for less than 12 months then you may not be able to make savings that cover the boiler installation cost of the smart heating controls.

That said, professional installation isn’t a must for many smart thermostats. So, if you’re happy with a little and sorting out the wired connection, then this might not be a problem.

Where the home is poorly insulated

Before investing in a smart boiler system, it would make more sense to ensure that your home is energy efficient to begin with.

Not only is poor insulation going to mean higher energy usage and bills, but it’s also going to mean an increased carbon footprint. Even with the best combi boiler or the most powerful system boiler, it will struggle if your home is not insulated properly.

People without a smartphone

If you don’t have a smartphone or tablet then the value that you get from smart controls are going to be minimal.

If you are, though, interested in how smart thermostats work and are curious as to what is a smart boiler, then a first step might be becoming familiar with smart devices such as a phone.

How long before a smart thermostat pays for itself?

So, you might be thinking that this all sounds very interesting but in the back of your mind, you’re wondering how long is it going to take before it begins to pay for itself. Well, pretty much all the manufacturers make claims as to how much smart boilers can save the homeowner.


Hive, for example, state that there are five different ways to reduce energy bills using their system and they provide a calculator that you can use to work out how much you could save before making a purchase. You can also use this boiler size calculator if you need help choosing the right size boiler.

Tado claims that it pays for itself after one to two years and is able to reduce your heating bill by up to 31%.

The difficulty with these types of figures is that they are the maximum saving that you’ll make if you are never really worried about your heating bill before you got the smart thermostat installed.

If you were already using manual controls such as a thermostat on the wall or using the control panel on the boiler, then it’s unlikely that you’ll make such big savings.

Are smart boilers the answer?

Smart boilers provide all kinds of functionality and convenience. However, if your focus is on saving money and you’re already on top of your energy usage, then looking at a new boiler with a higher level of energy efficiency might be the best route to making greater savings.

energy efficiency

And don’t forget, that many manufacturers now include technology with their system that could make them the best smart boiler option for you.

We admit though, that find the right new boiler quote might seem like a big task but we’re here to help.

Simply enter a few details about your home and energy needs and we’ll search our database to present you with the very best and personalised new boiler options.

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