A smart thermostat gives you more control over when and how you heat your home, with features such as app control, flexible schedules and, on some systems, individual room control. However, the best option depends on your boiler and how much control you actually need.
Our best overall smart thermostat for boilers is the tado° Smart Thermostat X (2nd gen). It combines broad boiler compatibility with Matter and Thread support and can be expanded with smart radiator thermostats. Drayton Wiser is particularly good for multi-room heating, while Hive offers a simpler alternative for homeowners who mainly want straightforward smart control.
Best smart thermostats for boilers at a glance
| Smart thermostat | Best for | Multi-room control | OpenTherm | Subscription required? |
| tado° Smart Thermostat X (2nd gen) | Best overall | Yes | Yes, compatible systems | No, but some features cost extra |
| Drayton Wiser | Multi-room heating | Yes | Yes, with compatible setup | No |
| Hive Thermostat | Simplicity | Yes, with radiator valves | Check compatibility/setup | No, but Hive+ adds features |
| Google Nest Learning Thermostat (3rd gen) | Automatic learning | Limited compared with Wiser/tado° | Yes | No |
| Honeywell Home smart controls | Straightforward alternative | Depends on system | Depends on model | Generally no |
Compatibility varies between boilers and installations, so check your specific boiler before buying.
1. tado° Smart Thermostat X (2nd gen) – Best overall
Best for: A feature-rich system that can grow with your home
The tado° Smart Thermostat X is our best overall choice because it offers a good balance between boiler control, smart-home compatibility and the option to build a more sophisticated multi-room heating system.
There’s also a brand-new thermostat at the centre of the system. tado° launched its second-generation Smart Thermostat X on 2 September 2026. It retains compatibility with the existing X range while introducing a thinner design, circular touch interface, programmable button and USB-C rechargeable battery rated for more than a year between charges.
The X platform supports Matter and Thread (smart-home standards that help devices from different brands connect and communicate reliably), making it particularly attractive if you want your heating to form part of a wider smart-home setup. It can also be expanded with Smart Radiator Thermostat X devices for room-by-room control.
Boiler compatibility is another strength. Depending on the installation, tado° X can provide conventional relay control or communicate digitally with compatible OpenTherm boilers.
What we like
- Strong combination of heating and smart-home features
- Relay and OpenTherm options
- Expandable with smart radiator thermostats
- Matter and Thread support
- Second-generation thermostat has rechargeable battery
- Good option for building a whole-home heating system
What to consider
The main drawback is that some of tado°’s more advanced automation sits behind its AI Assist subscription.
AI Assist costs £3.99 per month or £29.99 per year and includes features such as automatic geofencing, Adaptive Heating, advanced Open Window Detection and Pre-heat Before Arrival.
You can use the system without subscribing, but it’s worth considering whether the features you’re buying it for are included as standard.
Compatibility also needs checking carefully if you’re replacing an older tado° system or using a boiler with proprietary digital controls. The X range isn’t simply a direct replacement for every older tado° configuration.
Verdict: The best all-round option if you want more than basic app control and may eventually expand into room-by-room heating.
2. Drayton Wiser – Best for multi-room heating
Best for: Larger homes where different rooms need heating at different times
Drayton Wiser is our preferred option if room-by-room heating control is your priority.
The system can be expanded using smart radiator thermostats and additional room thermostats, allowing different areas to have their own schedules and target temperatures. The current system can control up to 16 rooms using up to 63 Wiser devices, giving it plenty of room to expand.
This can be particularly useful in a larger house. You might want a home office warm during working hours, living areas heated in the evening and bedrooms heated around bedtime rather than running every radiator according to one central schedule.
Wiser also supports OpenTherm with compatible equipment, allowing suitable boilers to use digital modulation rather than simple on/off control.
Another advantage is that there’s no subscription fee for Wiser’s core smart-heating system.
What we like
- Excellent room-by-room expandability
- Up to 16 rooms
- Smart radiator thermostat support
- OpenTherm support with compatible setups
- Useful Eco, Comfort and Away modes
- No subscription for core features
What to consider
The cost rises as you add radiator thermostats throughout the house. If you only want to turn your heating on and off remotely, you’re unlikely to get much benefit from Wiser’s strongest feature.
Verdict: One of the best choices for larger homes where multi-room control matters more than having a particularly stylish central thermostat.
3. Hive Thermostat – Best for simplicity
Best for: Straightforward app control without an overly complicated setup
Hive is a good choice for homeowners who want to make their heating smarter without turning it into a major home-automation project.
You get the features most people expect from a smart thermostat: remote control from a phone, heating schedules, boosts and integration with other smart-home devices. Hive also offers smart radiator valves if you want to add more granular room control later.
The standard Hive Thermostat currently costs £119, while the smaller Thermostat Mini costs £79 before installation or promotional discounts.
The main distinction to understand is between standard Hive functionality and Hive+.
Basic scheduling and heating boosts don’t require Hive+. The optional subscription currently costs £3.99 per month or £39.90 per year and adds features such as Saver Mode, Schedule Assist, budgeting tools and extended warranty benefits.
What we like
- Straightforward app-based control
- Easy-to-understand ecosystem
- Standard scheduling doesn’t require a subscription
- Smart radiator valves available
- Choice between standard thermostat and cheaper Mini
What to consider
Some of the more sophisticated energy-management features now sit within Hive+, so compare the free and paid functionality before deciding.
If advanced boiler modulation or extensive multi-room control is your main priority, tado° or Wiser may also deserve a closer look.
Verdict: A sensible option if convenience and simplicity are more important to you than having the most advanced heating controls.
4. Google Nest Learning Thermostat – Best for learning your routine
Best for: Homeowners who want the thermostat to build its own schedule
The third-generation Google Nest Learning Thermostat takes a somewhat different approach.
Instead of relying entirely on schedules you create yourself, Nest can learn from your temperature adjustments and use them to create an automatic heating schedule.
The UK version uses a Heat Link connected to the heating system and supports both conventional on/off control and OpenTherm for heating and hot water.
It’s also one of the more visually distinctive thermostats in this comparison, with a colour display designed to remain visible rather than being hidden away.
However, at £219 from Google’s UK Store, it’s relatively expensive compared with some alternatives.
Its approach to room-by-room radiator control also isn’t as compelling as the expandable heating ecosystems offered by tado° and Wiser.
What we like
- Learns your heating routine
- OpenTherm support
- Heating and hot-water control on compatible systems
- Attractive physical thermostat
- Good choice if you don’t want to build schedules manually
What to consider
- Relatively high purchase price
- Less compelling for extensive radiator-by-radiator control
- An older UK product than the newly released tado° X
Verdict: Still worth considering if automatic schedule learning is the feature you care about most.
5. Honeywell Home – Best straightforward alternative
Best for: Homeowners who want established heating controls without prioritising a wider smart-home ecosystem
Honeywell Home, now part of Resideo, offers several smart-heating controls rather than one system that fits every property.
That can be an advantage if you’re primarily interested in heating control rather than building an ecosystem around a particular consumer smart-home brand.
However, it also makes compatibility more important. Features such as hot-water control, zoning and boiler modulation vary according to the particular Honeywell Home system and installation.
For that reason, we’d treat Honeywell Home as a strong alternative to investigate with your installer, rather than recommending one model as universally suitable.
Verdict: Worth considering if you prioritise established heating-control hardware and can match the appropriate system to your boiler.
How we chose the best smart thermostats
The best thermostat isn’t necessarily the model with the longest list of app features.
We prioritised factors that make a meaningful difference to a UK boiler installation:
- Boiler compatibility
- OpenTherm or modulating-control options
- Multi-room expandability
- Smart radiator thermostat support
- Scheduling and automation
- Subscription requirements
- Ease of everyday use
- Smart-home compatibility
We also considered whether each system suits a particular type of household rather than trying to declare one thermostat best for everyone.
Will a smart thermostat work with any boiler?
No. Check compatibility before buying.
Most smart thermostats can control a wide range of UK gas boilers, but the level of control they provide can vary.
There are two particularly important types of boiler communication.
Relay control
A conventional relay thermostat essentially tells the boiler whether there is a demand for heat.
When the temperature falls below the target, it requests heat. Once the target has been reached, the demand stops.
This approach works with many boilers and can still give you useful smart features such as remote control and schedules.
OpenTherm
OpenTherm allows compatible controls and boilers to communicate digitally.
Rather than relying entirely on an on/off demand, a compatible thermostat can request different levels of heat output. This can allow the boiler to operate more efficiently under suitable conditions.
Both tado° X and Drayton Wiser offer OpenTherm options for compatible installations, while the UK Nest Learning Thermostat’s Heat Link supports both on/off and OpenTherm control.
Don’t assume that a thermostat advertised as OpenTherm compatible will automatically provide OpenTherm control with your boiler. Both sides of the installation need to be compatible and connected appropriately.
What smart thermostat do you need for a combi boiler?
A combi boiler generally makes smart-thermostat selection relatively straightforward because there’s no separate hot-water cylinder to schedule.
The thermostat primarily controls the central heating, while the boiler produces domestic hot water when you open a hot tap.
The important questions are therefore whether the thermostat works with your particular combi and whether it can take advantage of any modulating control the boiler supports.
For a basic combi setup, you may not need an expensive multi-channel heating controller.
What about system and conventional boilers?
System and conventional boilers can introduce another requirement: stored hot-water control.
If you have a hot-water cylinder, check whether the thermostat system can control its schedule as well as your central heating.
Nest’s UK Heat Link, for example, supports on/off and OpenTherm control for heating and hot water.
The appropriate hardware can therefore differ from what you’d buy for a simple combi-boiler installation.
This is one reason it’s worth using the manufacturer’s compatibility checker or discussing the system with your installer before ordering anything.
Do you need smart radiator thermostats?
Not necessarily.
A central smart thermostat can still provide remote control, schedules and other useful automation without changing the valves on every radiator.
Smart radiator thermostats become more valuable when you want different heating schedules for different rooms.
Equipping every radiator adds considerably to the overall cost. In a small home that’s normally occupied throughout the day, a central smart thermostat may provide most of the functionality you actually need.
Can a smart thermostat reduce heating bills?
Potentially, but there isn’t one percentage that applies to every home.
Smart thermostats can reduce unnecessary heating by making it easier to create accurate schedules, turn the heating down when you’re away and control individual rooms where compatible equipment is installed.
Some manufacturers publish much larger potential savings. tado° says its customers save an average of 22% on heating costs, while Wiser cites potential savings of up to 30% based on research it references.
These shouldn’t be interpreted as guaranteed savings for your home.
Someone replacing an old timer and poor heating routine has much more opportunity to save than someone who already uses efficient controls and carefully manages their heating.
Are smart thermostats worth it?
A smart thermostat is most worthwhile when you’ll actually use the additional control it provides.
If your schedule changes frequently, being able to adjust the heating remotely can prevent you from heating an empty house. Multi-room systems can be particularly useful if different rooms are occupied at different times.
A smart thermostat may provide less benefit if you already have effective heating controls, follow a consistent schedule and rarely need to make adjustments.
Also consider the total system cost, not just the price of the thermostat. Professional installation, additional receivers and multiple smart radiator valves can make a sophisticated multi-room system considerably more expensive than its starter kit.
Frequently asked questions
What is the best smart thermostat for a combi boiler?
We rate the tado° Smart Thermostat X (2nd gen) as the best overall option, but the right choice depends on your specific combi. Check whether your boiler uses standard relay control, OpenTherm or another digital control system before buying.
Can I install a smart thermostat myself?
Some parts of smart-heating systems are designed for DIY setup, but installing a boiler receiver or replacing wired heating controls can involve mains electricity and connections to the heating system. Follow the manufacturer’s installation requirements and use a suitably qualified installer where necessary.
Does a smart thermostat need Wi-Fi?
Smart features such as remote app control generally require an internet connection. What happens if your broadband goes down varies by system, although heating controls typically retain some local functionality rather than leaving you unable to heat the house.
Can you use smart radiator valves without a smart thermostat?
Some systems allow different configurations, but for full room-by-room boiler control it’s usually best to use radiator thermostats as part of the manufacturer’s wider heating system. Check how the particular ecosystem handles heat demand before buying individual valves.
Do smart thermostats work with old boilers?
Many do. A boiler doesn’t necessarily need to be new to use a smart thermostat. Older boilers may be limited to basic relay control rather than more sophisticated modulation, so check the exact boiler model and existing controls.
Sources
tado°, Smart Thermostat X (2nd gen) launch, 2 September 2026 – https://www.tado.com/en/press/tado-presents-new-smart-thermostat-x-2nd-gen-its-thinnest-and-most-intuitive-thermostat-yet
Drayton Wiser, Smart Room Thermostat – https://wiser.draytoncontrols.co.uk/products/smart-room-thermostat
Drayton Wiser, Smart Home Heating Kits – https://wiser.draytoncontrols.co.uk/collections/smart-home-heating-kits
Drayton Wiser, Multi-room heating and OpenTherm product information – https://wiser.draytoncontrols.co.uk/sites/default/files/wiser_datasheet_d126-7.pdf
Hive, Smart Heating Guides – https://www.hivehome.com/guides/hive-heating
Hive, Smart Heating products and current prices – https://www.hivehome.com/guides/hive-heating
Hive, Hive+ Membership – https://www.hivehome.com/shop/smart-heating/hive-plus
Google Store UK, Nest Learning Thermostat – Technical Specifications – https://store.google.com/gb/product/nest_learning_thermostat_3rd_gen_specs?hl=en-GB
Accurate as of: 5 September 2026