Best Smart Thermostat for System and Regular Boilers UK (2026)
Have a hot water cylinder? System and regular (heat-only) boilers need smart controls that can schedule stored hot water as well as heating. We compare tado° X, Honeywell Home evohome, Drayton Wiser, Hive and Google Nest on exactly that.
- Independent research
- Hot water cylinder control compared
- Affiliate links disclosed
Quick answer: what is the best smart thermostat for a system or regular boiler?
See full recommendationsIf your boiler heats a hot water cylinder, choose a smart system that controls both heating and hot water. All five systems on this page can do that with the right kit, but the hardware and level of hot water control differ. For many homes, tado° Smart Thermostat X (2nd gen) with the Wireless Receiver X is our best overall choice.
tado° Smart Thermostat X (2nd gen)
Relay and OpenTherm on compatible systems, with excellent zoning via tado° X radiator thermostats.
Read our notes
Honeywell Home evohome
Up to 12 zones. Best for larger or complex homes.
Read our notes
Drayton Wiser
Very good zoning. An excellent-value zoning system.
Read our notes
Hive Thermostat
Suitable for many common UK boiler setups. An easy everyday option.
Read our notes
Google Nest Learning Thermostat
Limited zoning. The best smart-home experience.
Read our notesImportant: Compatibility depends on the exact boiler model, existing wiring and whether your system uses simple relay control, OpenTherm or a manufacturer-specific digital control. Check the kit is the heating and hot water version, not a heating-only version for combi boilers.
Affiliate disclosure: This page contains Amazon affiliate links. If you buy through one of these links, Heat Pump Guide UK may earn a commission at no extra cost to you. Affiliate relationships do not determine our recommendations.
How we chose these thermostats
This guide was independently researched to help UK homeowners compare smart heating systems based on practical factors including boiler compatibility, zoning, ease of use, expandability and everyday value. Product compatibility and features were checked against manufacturer information. Always confirm compatibility against your exact boiler and heating system before purchasing.
- Boiler compatibility: relay, OpenTherm or manufacturer controls
- Stored hot water control for cylinder systems
- Room-by-room zoning options
- Ease of use day to day
- Expandability over time
- Everyday value
Hot water control compared
Details below come from manufacturer and retailer product information checked on 15 October 2026. Kits and features change, so confirm the exact part before ordering.
| System | Hardware for hot water | What it controls |
|---|---|---|
| tado° X | Wireless Receiver X | Hot water schedules in the app, plus a 60-minute boost button on the receiver |
| Honeywell Home evohome | evohome Hot Water Kit (ATF500DHW), added to an evohome controller | Timed hot water with a target temperature. A wireless cylinder thermostat shows the live cylinder temperature, and boost is one tap |
| Drayton Wiser | Wiser Thermostat Kit 2 (two-channel HubR) | Separate hot water schedule alongside heating |
| Hive | Heating and Hot Water kit with a dual-channel receiver | Separate 7-day hot water schedule and boost of up to 6 hours |
| Google Nest Learning Thermostat | Heat Link | On/off control of heating and hot water. Google lists domestic hot water tanks and system and heat-only boilers as compatible |
Want to control cylinder temperature, not just timing? Of the systems here, evohome’s hot water kit is the clearest about sensing and targeting the cylinder temperature. Most of the others are best thought of as smart timers for your hot water.
Best smart thermostats for system and regular boilers in detail
Compatibility note: features such as OpenTherm depend on the thermostat version, boiler and installation configuration. Always check the exact combination before buying.
1. tado° Smart Thermostat X (2nd gen)
Best for: most UK homes with a system or regular boiler that want strong smart controls, OpenTherm or relay compatibility and the option to add room-by-room heating later.
The latest tado° Smart Thermostat X (2nd gen) is the strongest all-round choice for many gas-heated homes because it combines app control, flexible scheduling and support for both relay and OpenTherm control on compatible systems. It also sits within the newer tado° X ecosystem, so you can add Smart Radiator Thermostats X later and create different temperatures and schedules for individual rooms.
For hot water, tado° says system boiler homes should use the Wireless Receiver X, which lets you schedule hot water in the app and has a boost button that heats water for 60 minutes. The wired 2nd-generation thermostat supports relay and OpenTherm control on compatible heating systems and uses the newer tado° X platform with Matter and Thread connectivity.
Why tado° works well here
- Relay and OpenTherm support on compatible systems
- Strong app control and scheduling
- Expandable with tado° Smart Radiator Thermostats X
- Matter and Thread smart-home connectivity
- Built-in rechargeable battery, charged via USB-C
- Available in wired and wireless configurations
- Good upgrade path into room-by-room heating
Potential downside
- tado° X is a different platform from older tado° V3+ and earlier products, so existing older-generation devices cannot be mixed into the same tado° X Home
Why we recommend it: tado° gives the strongest overall combination of boiler control, app usability, expandability and modern smart-home support for many gas-heated homes.
Best for you if: you want a smart thermostat that can start with simple whole-house control and expand into a more complete smart heating system later.
Choose the right tado° X version
Already have tado° X or suitable Thread connectivity?
Wired Thermostat OnlyFirst tado° X setup with an existing wired thermostat?
Wired Starter KitReplacing a wireless thermostat or need a boiler-side receiver?
Wireless Starter KitBefore buying: check your exact boiler model, current thermostat wiring and whether your heating system uses relay, OpenTherm or manufacturer-specific controls.
2. Honeywell Home evohome
Best for: larger homes, multi-room properties and homeowners who want significantly more room-by-room control than a conventional smart thermostat provides.
Honeywell Home evohome is different from most of the products on this page. Rather than simply replacing one central thermostat, it is designed as a complete multi-zone heating control system. evohome can manage up to 12 individual heating zones, so bedrooms, living areas, home offices and other parts of the property can follow different temperatures and schedules. That can be particularly useful in larger gas-heated homes where one thermostat in a hallway is a poor representation of the temperature throughout the property.
Why evohome works well here
- Control of up to 12 individual heating zones
- Excellent option for larger radiator-based homes
- Works with compatible on/off boiler configurations
- OpenTherm boiler control is possible with appropriate evohome hardware
- Compatible Honeywell Home radiator controllers provide individual room control
- Can incorporate underfloor heating
- Can incorporate stored hot-water control
- Well suited to more complex heating layouts
Potential downside
- A complete evohome installation is more involved and can require several components
- It makes less sense for a small home where you only want basic app control
Why we recommend it: if zoning is your main priority, evohome offers substantially more control than a conventional single smart thermostat.
Best for you if: you have a larger house, different rooms are occupied at very different times, or you specifically want a whole-home zoned heating system.
3. Drayton Wiser
Best for: homeowners who want a practical room-by-room smart heating system without paying for a more premium zoning setup.
Drayton Wiser is one of the strongest alternatives to tado° if smart radiator control is important to you. You can start with the main Wiser heating control and then add Wiser Smart Radiator Thermostats in individual rooms. That makes it particularly useful in family homes, older properties and homes where bedrooms, offices and living spaces are used at different times.
Why Wiser works well here
- Strong value for multi-room heating control
- Good smart radiator thermostat ecosystem
- Useful room-by-room scheduling
- Straightforward app control
- Can be expanded gradually
- Good alternative to tado° for zoning
Potential downside
- Exact boiler functionality depends on which Wiser kit and boiler configuration you use, so check the system rather than buying on the Wiser name alone
Why we recommend it: Wiser gives you many of the practical benefits of a more advanced multi-room system without necessarily requiring the investment of something such as evohome.
Best for you if: you want smart room-by-room heating but also care about keeping the total system cost sensible.
4. Hive Thermostat
Best for: homeowners who mainly want straightforward app control and easier heating schedules.
Hive remains one of the easiest smart heating systems for many UK homeowners to understand. If your current controls are awkward, dated or difficult to programme, Hive provides a relatively straightforward step into app-controlled heating. It does not need to be the most technically advanced thermostat to make sense. Its strength is that the app, thermostat and scheduling are easy to use day to day.
Why Hive works well here
- Simple app control
- Easy heating schedules
- Familiar UK heating brand
- Good replacement for basic timers and thermostats
- Can be expanded with compatible Hive radiator valves
- Good choice if simplicity matters more than advanced modulation
Potential downside
- If advanced zoning or detailed boiler modulation is your priority, tado°, Wiser or evohome may suit you better
Why we recommend it: Hive remains one of the easiest options for homeowners who do not want to spend time configuring a more complicated smart heating system.
Best for you if: you mainly want reliable app control, sensible schedules and a thermostat that is easy for the whole household to use.
5. Google Nest Learning Thermostat
Best for: homeowners who value smart-home integration, automation and premium thermostat design.
The Google Nest Learning Thermostat remains one of the best-known smart thermostats and is especially appealing if you already use Google smart-home products. Its main strength is automation. Rather than focusing heavily on radiator-by-radiator zoning, Nest is built around intelligent whole-home thermostat control and integration with the wider Google ecosystem.
Why Nest works well here
- Strong Google smart-home integration
- Learning and automation features
- Premium physical design
- Good app experience
- Useful for homeowners who prefer automation to manual scheduling
Potential downside
- Its room-by-room heating capabilities are more limited than tado°, Wiser or evohome
Why we recommend it: Nest remains a polished option if you want your thermostat to form part of a wider smart home rather than building a detailed radiator zoning system.
Best for you if: you already use Google devices around the home and prefer automation and design over advanced zoning.
Which smart thermostat is best for your boiler setup?
Match your situation to the system that suits it, then confirm compatibility for your exact boiler.
| Your situation | Best choice | Why |
|---|---|---|
| You want the best all-round smart thermostat | tado° X (2nd gen) | Strong boiler compatibility, app control and room-by-room expansion |
| You have a larger home and want advanced zoning | Honeywell Home evohome | Can control up to 12 separate heating zones |
| You want affordable room-by-room control | Drayton Wiser | Strong smart radiator ecosystem at sensible whole-home cost |
| You want the easiest system to use | Hive | Simple app and straightforward schedules |
| You already use Google smart-home products | Google Nest | Strong automation and Google ecosystem integration |
| Your boiler supports OpenTherm | tado° or suitable evohome configuration | Can use digital modulating control where the complete system supports it |
Why upgrade your boiler controls?
Many UK homes still use basic programmable thermostats, older wireless controls or heating timers. They may work reliably, but they often give you much less control over when and where your heating runs. A suitable smart thermostat can help you:
- Control your heating remotely from an app
- Create more flexible heating schedules
- Reduce heating when nobody is home
- Avoid overheating the house unnecessarily
- Adjust heating more easily as routines change
- Add room-by-room control with compatible smart radiator valves
- Use modulating boiler control where both thermostat and boiler support it
A smart thermostat does not automatically make the boiler itself more efficient. Any reduction in energy use normally comes from better schedules, lower unnecessary temperatures, zoning or improved boiler control.
Which smart thermostat saves the most money?
There is no thermostat that automatically guarantees the biggest saving. The largest real-world improvements normally come from changing the way the heating is controlled:
- Reducing temperatures when nobody is home
- Using better heating schedules
- Avoiding overheating
- Heating occupied rooms rather than the entire property
- Reducing unnecessary heating overnight
- Using suitable smart radiator controls
- Taking advantage of modulating control where the boiler supports it
This is why tado°, Drayton Wiser and evohome can be particularly attractive in homes where zoning would genuinely change heating behaviour. In a small, evenly heated home, however, a simpler Hive setup could provide nearly all the control you actually need.
Do smart thermostats really save money?What is OpenTherm and does it matter?
A basic thermostat often controls a boiler using a simple on/off signal. When the thermostat calls for heat, the boiler turns on. Once the target temperature is reached, it turns off.
OpenTherm allows compatible thermostats and boilers to communicate digitally. Instead of simply requesting full heat or no heat, the thermostat may be able to influence how hard the boiler needs to work. That can allow a compatible modulating boiler to operate more steadily rather than repeatedly running at unnecessarily high output.
Do not assume your boiler uses OpenTherm
Some boilers use OpenTherm, some use ordinary relay controls and others use their manufacturer’s own digital communication system. A thermostat advertising OpenTherm support does not automatically mean your exact boiler can use it.
If you have a modern combi boiler, our dedicated smart thermostat for combi boilers guide explains this in more detail.
Have a combi boiler instead?
A combi boiler heats hot water on demand, so you do not need hot water scheduling or a two-channel kit. The thermostat’s main job is central-heating control, and our best smart thermostat for combi boilers guide covers that in detail. For many combi boiler homes:
- tado° X: strongest overall mix of relay/OpenTherm compatibility and expansion
- Drayton Wiser: particularly good if you want affordable radiator zoning
- Hive: best if simplicity is the priority
- Nest: strongest if smart-home automation matters more than multi-room control
Smart thermostat or smart TRVs?
They solve different problems.
Smart thermostat
Controls the main heating demand and schedule.
- Best if your current heating controls are basic
- Useful for app control
- Improves whole-home scheduling
- Can provide boiler modulation on suitable systems
Smart TRVs
Control individual radiators or rooms.
- Useful if spare rooms are overheated
- Good for bedrooms used at different times
- Useful for home offices
- Better for unevenly heated houses
For many larger homes, the best solution is a compatible smart thermostat plus smart radiator controls in rooms where individual schedules are genuinely useful.
What to check before buying a smart thermostat
Six checks that prevent most compatibility problems.
Your exact boiler model
Do not rely only on the boiler brand. Two boilers from the same manufacturer may use different control systems.
Relay, OpenTherm or manufacturer-specific controls
Check how your existing thermostat communicates with the boiler and whether you will retain or lose any manufacturer-specific modulation features.
Wired or wireless thermostat
If you are replacing an existing wired wall thermostat, a wired smart thermostat may be simplest. Other homes may require a wireless receiver at the boiler.
Hot-water control
Combi boilers usually provide hot water on demand. Conventional and system boilers may use a hot-water cylinder, which means you need to consider whether the smart control also needs to manage stored hot water.
Whether you want zoning
If room-by-room heating is important, look at the complete thermostat and smart radiator ecosystem rather than the thermostat in isolation. Our broader smart heating controls guide brings together the main thermostat and radiator-control options.
Your existing smart-heating equipment
If you already own smart radiator thermostats or other heating controls, check whether a newer thermostat can actually work with them.
tado° owners should note: tado° X uses a different technology platform from older tado° V3+ and earlier systems. The two product generations cannot be mixed within the same tado° Home.
Common mistakes when buying a smart thermostat for a system or regular boiler
Buying the heating-only version
Many smart thermostats are sold in heating-only and heating-and-hot-water versions. If you have a cylinder and want app control of hot water, make sure the kit includes a two-channel receiver or the manufacturer’s hot water module.
Assuming every thermostat works with every boiler
This is the biggest mistake. Compatibility should be checked before price, design or app features.
Choosing purely on brand
tado°, Hive, Nest, Wiser and evohome are all good systems, but they solve slightly different problems.
Paying for advanced zoning you will never use
evohome is extremely capable, but it may be excessive in a small two-bedroom house where the whole property follows roughly the same heating schedule.
Ignoring smart radiator valves
If your main problem is that different rooms need different temperatures, replacing the central thermostat alone may not solve it.
Expecting guaranteed energy savings
A smart thermostat is a control tool. Savings depend on how it changes your heating behaviour and how efficiently the rest of the system operates.
Forgetting installation costs
Some systems are straightforward replacements while others may require an installer or additional receiver and zoning hardware. Compare the complete installed system rather than just the thermostat price.
Our verdict: best smart thermostat for system and regular boilers
For most UK homes with a system or regular boiler, tado° Smart Thermostat X (2nd gen) with the Wireless Receiver X is our best overall choice because it combines modern smart controls, relay and OpenTherm compatibility on suitable systems and a strong route into room-by-room heating.
Honeywell Home evohome is our preferred option where advanced multi-room zoning is the main priority, particularly in larger houses. Drayton Wiser remains the strongest value alternative for room-by-room control, while Hive is our easiest recommendation for straightforward smart heating. Google Nest remains attractive for homeowners who prioritise design, automation and Google smart-home integration.
- Choose tado° X for the best all-round system
- Choose evohome for serious whole-house zoning
- Choose Wiser for value room-by-room control
- Choose Hive for simplicity
- Choose Nest for smart-home automation
Start with boiler compatibility, then decide whether you simply need better whole-house control or want to build a room-by-room heating system.
Frequently asked questions
What is the best smart thermostat for a system or regular boiler?
For many UK homes, tado° Smart Thermostat X (2nd gen) with the Wireless Receiver X is our best overall choice because it combines strong app control, hot water scheduling and room-by-room expansion. evohome is the stronger choice if you want cylinder temperature control.
Can a smart thermostat control my hot water cylinder?
Yes, with the right kit. tado° X, Hive, Drayton Wiser, evohome and Nest all offer hot water control for cylinder systems, but you usually need the heating-and-hot-water version or an extra receiver or hot water kit.
What is the best smart thermostat for a large house?
Honeywell Home evohome is particularly strong for larger properties because it can control up to 12 individual heating zones. tado° and Drayton Wiser are also strong options if you want smart radiator control across several rooms.
Is OpenTherm better than simple on/off boiler control?
OpenTherm can allow a compatible thermostat and boiler to communicate using modulating control rather than only switching heating on and off. Whether this provides an advantage depends on the boiler, system design and control configuration.
Will a smart thermostat lower my gas bill?
It can reduce wasted heating if it helps you use better schedules, lower unnecessary temperatures or avoid heating unused rooms. Savings are not guaranteed and depend on how the heating is currently used.
Is Hive or tado° better for a gas boiler?
tado° is generally the stronger choice if you want OpenTherm compatibility on suitable boilers, more advanced controls and room-by-room expansion. Hive is generally easier if your priority is straightforward app control and scheduling.
Is Honeywell evohome better than tado°?
It depends on the property. evohome is particularly strong for advanced multi-zone control in larger homes. tado° is easier to recommend as a more general-purpose smart thermostat with a simpler route into room-by-room heating.
Do I need smart radiator valves as well?
No. A smart thermostat can work perfectly well without smart radiator valves. TRVs become more useful when different rooms need different schedules or temperatures.
Can I use old tado° radiator thermostats with the new tado° X thermostat?
No. tado° X devices use a different platform from older V3+ and earlier tado° products and cannot be combined within the same tado° Home.
Related guides
Best Smart Thermostat for Combi BoilersHeating-only control for on-demand hot water
Best Smart Thermostat for Older HomesControls for draughty, uneven properties
Best Smart TRVsRoom-by-room radiator control compared
Smart Thermostat vs Smart TRVWhich upgrade solves your problem
Are Smart Thermostats Worth It?What you actually gain from an upgrade
Do Smart Thermostats Save Money?What affects any savings on your bills
Hive vs tado°Two popular smart heating systems compared
Hive vs NestSimplicity against automation
Gas Boiler to Heat Pump UKWhat changes if you switch later
Sources and further reading
Product compatibility and features were checked against current manufacturer information. Always confirm compatibility against your exact boiler and heating system before purchasing.
- tado°: Wired Smart Thermostat X (2nd gen)
- tado°: tado° X compatibility with older products
- Resideo: Honeywell Home evohome
- Honeywell Home: evohome System Builder
- Energy Saving Trust: Thermostats and heating controls
- tado°: Can I control hot water with Smart Thermostat X?
- Google Store: Nest Learning Thermostat specifications
- Hive V4 Heating & Hot Water kit: product details
- Drayton Wiser Thermostat Kit 2: product details
- Honeywell Home evohome Hot Water Kit (ATF500DHW): product details