Smart Thermostats Explained: Features, Benefits and the Best Options for Your Home

Smart Thermostats Explained: Features, Benefits and the Best Options for Your Home

Smart thermostats promise better control and the potential to reduce energy use.

Government-reviewed research suggests that smarter heating controls can produce savings by adapting heating around occupancy and demand, although the results depend heavily on the property, insulation, weather and household habits.

However, they are not tiny boxes of domestic sorcery.

A smart thermostat cannot repair poor insulation, resize an unsuitable radiator or breathe new life into a boiler that should have retired three winters ago. What it can do is give you more precise control over when and how your heating runs.

That can make your home more comfortable while helping you avoid heating empty rooms or running the boiler longer than necessary.

What Is a Smart Thermostat?

According to the Energy Saving Trust, smart heating controls perform the same basic functions as conventional heating controls, but internet connectivity provides additional ways to manage your system.

A smart thermostat monitors the temperature inside your home and communicates with the boiler. When the temperature falls below your chosen setting, it signals the heating system to switch on. Once the target temperature is reached, it reduces or stops the demand for heat.

Most smart thermostats connect to your home Wi-Fi and a smartphone app. This allows you to adjust the temperature, change schedules or switch the heating on and off while you are away from home.

Depending on the model, a smart thermostat may also learn your routine, use your phone’s location to recognise when the property is empty, respond to weather information or connect with compatible smart speakers and radiator controls.

These features can make it easier to match your heating schedule to your household’s routine rather than relying on one fixed programme throughout the week.

How Do Smart Thermostats Work?

A typical smart thermostat system includes:

• A thermostat or temperature sensor inside the home
• A receiver connected to the boiler
• An internet connection or smart hub
• A mobile app used to manage the system

When the thermostat detects that the room temperature has fallen below your chosen setting, it asks the boiler to produce heat.

Once the target temperature is reached, it tells the boiler to stop or reduce its output.

More advanced controls may use load compensation or technologies such as OpenTherm to communicate with a compatible boiler. Instead of simply switching the boiler fully on and off, these controls can adjust its output according to the amount of heat the home needs.

Jargon Buster: OpenTherm
A digital communication protocol that allows a smart thermostat and a boiler to talk directly to one another, precisely modulating the boiler’s output to match the exact heat demand of the home, rather than simply turning it on and off.

This can help a modern condensing boiler operate more steadily and efficiently.

Compatibility matters, though. Not every smart thermostat can use every feature with every boiler.

What Can You Do With a Smart Thermostat?

Smart thermostats vary considerably, but most provide a core group of useful functions.

Control Your Heating From Your Phone

App control allows you to adjust the heating from the sofa, office or train home.

You might switch it off after leaving unexpectedly, turn it down when plans change or warm the house before arriving home.

This remote control is one of the simplest benefits, but it can also prevent energy being wasted when nobody is home.

Create More Flexible Heating Schedules

Traditional programmers can be awkward to adjust, particularly when your routine changes between weekdays and weekends.

Smart thermostats generally make scheduling easier.

You can create different heating periods for different days and adjust them through an app rather than prodding a tiny collection of plastic buttons with the tip of a pen.

Use Away or Holiday Modes

Away modes reduce unnecessary heating when the property is empty.

Some thermostats require you to select this manually. Others can use phone location data or occupancy detection to recognise when household members have left.

Holiday modes can maintain a lower background temperature while you are away, helping protect the property without heating it as though everyone were still at home.

Control Different Areas of the Home

Some systems can work with smart thermostatic radiator valves.

These allow you to set different schedules or target temperatures for individual rooms.

For example, you might warm the kitchen and bedrooms in the morning without heating a spare room that currently serves as storage for exercise equipment and good intentions.

Multi-zone control can be useful, but it normally requires additional compatible devices.

Use Voice Controls

Certain smart thermostats connect with platforms such as Amazon Alexa, Google Assistant or Apple’s smart-home ecosystem.

Once connected, you may be able to adjust the temperature or check the current setting using voice commands.

Voice control is convenient, although it should be treated as an extra feature rather than the main reason to select a thermostat.

Review Heating And Energy Information

Depending on the product, the app may show:

• How long the heating has been running
• Changes in temperature
• Heating patterns
• Estimated energy use
• Monthly efficiency reports
• Suggestions for improving schedules

These reports can help you spot inefficient habits.

However, the thermostat’s figures may be estimates rather than measurements of your actual gas consumption. Your energy bill or smart meter remains the better place to check how much energy you have used.

Can Smart Thermostats Lower Energy Bills?

Smart thermostats can help reduce energy use by making it easier to heat your home only when necessary.

Ofgem recommends using smart thermostats and heating controls to set your heating and hot water to run only when needed. The Energy Saving Trust also notes that the savings available from smart controls depend on factors such as how you previously managed your heating and how effectively you use the new system.

The largest improvements are generally available to households that previously:

• Left the heating running for long periods
• Used limited or inflexible controls
• Regularly heated an empty property
• Struggled to adjust their heating schedule
• Maintained unnecessarily high temperatures

Savings may be smaller in a home that already has an efficient boiler, effective controls and a carefully managed schedule.

As we referred to earlier, this government-commissioned report found that heating-control performance depends heavily on the property and how occupants use the technology. Poorly understood or frequently overridden controls may fail to deliver the expected savings and can sometimes increase consumption instead of reducing it.

A smart thermostat is therefore a useful tool rather than a guaranteed discount code for your gas bill.

Advantages and Disadvantages of Smart Thermostats

Smart thermostats offer plenty of useful features, but they also introduce additional costs, compatibility checks and a little more technology into the home. Here is a quick comparison of the main advantages and disadvantages.

Which Smart Thermostat Is Best?

There is no single best smart thermostat for every household.

The right choice depends on:

• Your boiler type
• The thermostat’s compatibility
• Whether you need heating and hot-water control
• Your existing smart-home devices
• Whether you want multi-zone heating
• Which features require a subscription
• Your available budget
• How much automation you actually plan to use

A beautifully designed thermostat is of limited value when it cannot communicate properly with your heating system.

Here are several common options homeowners may encounter.

SALUS iT800 Smart Thermostat

The SALUS iT800 is designed for homeowners who want app-based heating control without turning their hallway into the bridge of a small spaceship.

It supports remote temperature adjustment and programmable schedules through the SALUS Premium Lite app.

The thermostat may suit users who value straightforward controls, a modern display and remote access more than extensive smart-home automation.

WarmZilla has highlighted the SALUS iT800 as part of the manufacturer’s more recent connected-control range.

Potential benefits include:

• Smartphone control
• Programmable schedules
• A modern touchscreen interface
• Remote access to the heating
• Straightforward everyday operation

The installer should still confirm compatibility with your boiler and heating arrangement.

Hive Thermostat Mini

The Hive Thermostat Mini provides app-based heating control in a compact package.

Users can create schedules, adjust the temperature remotely and activate a temporary heating boost through the Hive app.

It can also form part of a wider Hive system, with compatible smart radiator valves providing greater room-by-room control.

Potential benefits include:

• Remote app control
• Heating schedules
• Boost mode
• Holiday functionality
• Compatibility with selected smart-home platforms
• Optional multi-room control

Some advanced services may require a Hive subscription, so check what is included before making a decision.

Google Nest Learning Thermostat

The Nest Learning Thermostat is known for gradually building a schedule around household behaviour.

It includes remote control, occupancy-related functions and energy-use information.

The European third-generation Nest Learning Thermostat can also communicate with certain compatible boilers through OpenTherm, although the available functions depend on the boiler and installation.

Potential benefits include:

• Learning and automated scheduling
• Remote app control
• Occupancy detection
• Energy history
• Smart-home integration
• OpenTherm support with compatible systems

Nest may appeal to households already using Google smart-home products, but you should verify boiler compatibility before purchasing.

Do You Need Professional Installation?

Some manufacturers describe their products as suitable for DIY installation.

However, fitting a smart thermostat can involve work on the boiler controls, receiver and electrical wiring.

Incorrect installation may stop the thermostat from working properly, damage components or prevent advanced features from operating.

Professional installation is particularly sensible when:

• The existing wiring is unclear
• The thermostat controls heating and hot water
• You have a system or heat-only boiler
• You want OpenTherm or load compensation
• The heating system uses multiple zones
• You are replacing the boiler at the same time

An installer can confirm compatibility, fit the controls correctly and explain how to use them.

Can You Fit a Smart Thermostat to an Old Boiler?

Possibly.

Many older boilers can work with smart thermostats using basic on-and-off control.

However, an older boiler may not support modulation, OpenTherm or some of the thermostat’s more advanced efficiency features.

The condition of the heating system also matters.

An Engineer’s View

A smart thermostat is a brilliant upgrade for any household, but it is only as good as the system it controls. Ensure your radiators are balanced and your boiler is in good health before expecting miracles on your energy bill.

– Matthew Powell, Engineer

Installing an expensive smart thermostat will not resolve:

• A boiler that regularly breaks down
• Poor insulation
• Incorrectly sized radiators
• Sludge or restricted circulation
• Faulty valves
• Uneven heating
• An unsuitable boiler for the property

That is why the controls should be considered as part of the complete heating system rather than a shiny Wi-Fi plaster placed over every efficiency problem.

Should You Upgrade The Thermostat Or The Boiler?

A thermostat upgrade may be enough when the boiler remains reliable, efficient and suitable for the property.

A wider heating upgrade may be worth considering when the boiler:

• Breaks down frequently
• Struggles to heat the home
• Is expensive to run
• Does not support modern controls
• No longer suits the household’s hot-water needs
• Is approaching the end of its practical lifespan

Pairing a compatible control with a new boiler also allows the products to be selected as one system.

This reduces the risk of purchasing a smart thermostat only to discover that your boiler cannot use the features that attracted you to it.

Let WarmZilla Take Care of the Controls

Choosing a smart thermostat should not require an evening spent decoding compatibility tables, wiring diagrams and product names apparently chosen by malfunctioning bingo machines.

WarmZilla can help you select a boiler and control package suited to your property, heating system and daily routine.

Our professional installers can confirm compatibility, fit the controls correctly and show you how to use them.

Start the WarmZilla online boiler survey today to compare suitable boilers and build a heating system that works around your home.

Frequently Asked Questions

Do Smart Thermostats Work Without Wi-Fi?

Most smart thermostats can continue controlling the heating locally if the internet connection fails. However, app access, remote adjustments and certain automated functions may stop working until the connection returns.

Can A Smart Thermostat Control Individual Radiators?

A standard smart thermostat normally controls the main heating system. Individual room control usually requires compatible smart thermostatic radiator valves or a zoned heating system.

Is It Worth Getting A Smart Thermostat With A New Boiler?

It often makes sense because the boiler and controls can be selected for compatibility and installed together. This can also ensure that supported efficiency features are configured correctly.