Smart thermostats: Nest vs Hive vs Evohome vs Heat Genius vs OWL vs Tado vs Salus iT500 vs Cosy vs Climote

Smart thermostats: Nest vs Hive vs Evohome vs Heat Genius vs OWL vs Tado vs Salus iT500 vs Cosy vs Climote

Smart thermostats help you take control of your heating and make it more efficient. It’s about time that we took control of our heating bills because heating accounts for 60 per cent of household energy expenditure and 40% of British homes don’t even have a thermostat!

Which of the eight systems currently on the market do we like the most?

Smart heating should give many of us a Moon landing-like leap forward from basic on-off switches to heating which is ready when we’re in the home. Heating which we can adjust from our phones, wherever we are.

The companies providing the systems claim smart thermostats will save you around £200 a year as well, paying back their installation in the second year.

UK customers can currently buy eight smart thermostats: Hive from British Gas, Nest, Honeywell Evohome, Heat Genius, OWL Intuition, Tado, Salus iT500, Climote and – fresh out of Kickstarter – Cosy.

All of them work with a standard combi boiler, and some work with heating powered by LPG, biogas or oil, or underfloor heating, and even solar power. Many UK homes now have multi-zone systems so that bathrooms, bedrooms and different floors can be heated independently to save even more energy.

There’s also integration with other smart home devices to consider, like light switches and other power controls, monitoring your electricity usage, and even smoke detectors.

Smart thermostats: How much do they cost?

Prices for smart thermostats range from £139 (Salus iT500) to £249 (Heat Genius)The up-front cost of the kit isn’t everything: an easy way to tell a hobby system from something with long-term mainstream ambitions is to see if there’s an installation option in the price. Otherwise you’ll need the skills and confidence to deal with mains wiring and understand how your boiler is wired up.

From our sample, Nest, Hive, Evohome, Heat Genius, Tado, Climote and OWL Intuition all have installation options, ranging from £40 for the relatively simple Hive, to approved installers who will quote each job separately. Climote is only available with an installation, whether you buy it through their energy partners or direct. Heat Genius currently has a free installation offer, with no end date set as yet.

The Salus iT500 is the cheapest of the hobby-install systems at £139 on Amazon, while Hive comes in at £159 for the system or £199 with installation.

Honeywell Evohome, Heat Genius and Tado all come in close to £250 for the basic kit alone, and each has its benefits, with Evohome and Heat Genius boasting multi-room control (at an extra cost), while Tado claims it’s smart and easy to use.

As you’ll see below, if you’re thinking about a multi-room system this is only the tip of the iceberg.

Smart thermostat prices – updated Jan 2023

Installation – professional or DIY?

The installation option is recommended for anyone who isn’t comfortable wiring something into their mains power, or if you don’t already have a boiler control unit or wired-in thermostat.

You should also consider professional installation if you’re combining radiators with underfloor heating in a multi-zone system.

All of these systems can all be fitted DIY if you’re just replacing your existing boiler control unit or wired thermostat: it’s not a major challenge provided you know how to use your fusebox and put screws into a wall.

You’ll need to attach the new control unit to the wall, attach the power and attach the control wires for the boiler’s heating, and hot water if necessary.

If you’re building a multi-zone heating system, then it gets more complicated both and you’ll probably need an installer qualified for both plumbing and electrical work. Any significant new electrical installations will also need signing off by a qualified electrician to meet the conditions of your home’s building insurance.

What can a smart thermostat do? Hot water and multi-zone heating

There are still many homes which also heat water for storage in an insulated tank using a timer, and if you want to take control of this as well, then you’ll need Hive, Evohome, OWL Intuition, Climote or Salus – although Cosy plans to add hot water control in future. Nest doesn’t provide separate hot water control.

Hive, Climote and Salus simply turn your hot water on and off to fill the tank at a set time, while Evohome and OWL use an add-on thermostatic kit which also sets the temperature in your hot water tank.

If you’ve got a large detached home, or a large apartment, you should be considering multi-room or zoned heating so you only heat the rooms you’re using.

Evohome, Heat Genius, Nest, OWL Intuition, Climote and Salus all allow multi-room heating control, with Cosy and Tado planning to add it in future, but they do it in different ways.

Evohome uses wireless thermostatic radiator valves which sense the temperature and activate each radiator individually – they can be grouped together into as many as 12 zones around your home, along with underfloor heating controls. It’s not cheap: valves are about £60 each or £228 for four.

OWL Intuition is even more expensive, with each room requiring a separate thermostat or relay at around £90 per room, and a maximum of four rooms.

Heat Genius is the cheapest option for multi-room, with wireless thermostatic valves at £50 per radiator, and you can have up to 30 per home.

The Salus iT500 allows just one extra control zone, using the iT300 wireless remote sensor for £37.25, but it’s a choice between two-zone multi-room heating, or heating and hot water.

Climote comes with three zones as standard, one of which can be used for hot water, but these must be separately plumbed into your boiler.

The most expensive multi-room smart thermostat system is Nest: you have to install an individual £179 system for each zone you want to control, and you can have up to 10 per account, across two homes if you need.

smart thermostats - costs

How smart are smart thermostats? Learning, location and weather monitoring

Nest and Heat Genius use motion sensors to detect if people are in a room and automatically adjust the heating accordingly. There are big differences in the level of intelligence these systems apply to controlling your heating.

Hive, Evohome, Cosy, Salus, Climote and OWL all let you build temperature schedules for your day through a web browser or smartphone app interface. Hive offers just four temperature change points, the Salus iT500 lets you specify six, and the others are practically unlimited.

Nest, Heat Genius and Tado claim to be smarter than this: Nest learns how warm you like your home by encouraging you to set the temperature as you go over the first few days, but you can still set specific temperature points if you’re not satisfied by the schedule it creates. They also monitor the time it takes for your house to warm up, so they can switch on earlier to get to your comfort zone.

Unfortunately, remote connection is not an inclusive feature with Evohome, which charges £57 for a Mobile Access Kit, while the Hive, Evohome, Cosy, Salus, OWL, Heat Genius, and Tado systems all employ a hub which needs both a spare Ethernet port on your router and a power socket.

Climote and Nest use WiFi to communicate directly with your router, and they’re both designed to be installed in a fixed location. OWL Intuition offers the choice of fixed and wireless portable thermostats.

Nest also has a built-in infrared motion sensor which looks out for people moving around and turns off the heating if it thinks your house is empty.

Heat Genius allows you to add wireless motion sensors at £45 each, even placing them in different rooms to control the heating separately and learn how you move around the house to adjust your heating schedule automatically.

Tado uses geolocation information sent from your phone to predict when you’ll walk through the front door, making sure everything’s nice and warm when you get homeTado uses geolocation built into your phone to see who’s at home (or who’s coming home) and uses this information to fine tune your schedules, but you can override this for users without phones. Cosy plans to add a similar feature in a future software update.

Heat Genius, OWL Intuition, Tado and Nest also monitor the weather reports and forecasts so they come on later if it’s hot outside and your house warms up easily, or start heating early when there’s a cold snap.

As far as we’re able to tell, all of these systems allow you to set a minimum temperature to protect against frozen pipes in winter.

smart thermostat - mobile interfaces

How upgradeable and future-proof is it?

It would be welcome to see some scope for change in Hive, such as more heating time zones during the day, and multi-room heating support. It uses the Zigbee communication standard so there’s no reason it couldn’t interact with other devices in your home.

Nest seems to be more flexible product: it already combines with the Nest Protect smoke and carbon monoxide alarm to better detect people in your home and shut down your heating if there’s a rise in CO. The developers are in discussions with Mercedes so that its cars will announce your return home while you’re commuting, and with home home automation manufacturer Control 4 Home to integrate its devices into Nest: for instance opening and closing motorised curtains and air vents, or monitoring security sensors.

Tado will launch an air conditioning control system which would be complementary to its central heating control, and as another Zigbee-based system it could communicate with other devices.

The modular nature of Evohome, OWL Intuition, and Salus suggest a broader range of applications can be plugged in as the software develops. OWL and Salus both produce electricity monitoring components which can feed information to the smartphone app.

Heat Genius includes optional smart sockets, which will remotely switch on and off any devices connected to them, which opens the door to other automated devices.

Cosy includes smart plugs for switching mains devices on and off, and its Kickstarter page talks about integrating temperature and consumption data, as well as multi-room and hot water control, and stresses that the system is designed to be upgradeable.

OWL may be the most future-proofed of all for the green consumer – it can integrate and control a solar power system, even telling you how much you’re saved or sold back to the National Grid.

Climote doesn’t seem designed for any expansion into more advanced zone control and home automation, or learning how you live to improve its energy-saving abilities.

smart thermostats - compared

Smart thermostats: How easy are they to use?

We’ve lived with Hive and experienced demonstrations of Nest and Evohome. Nest is perhaps the easiest system to use and certainly has the most elegant thermostat, since all you have to do is tell it whether you’re happy with the temperature or not.

Hive and Evohome require more input, and as a single-zone system with only four time settings, Hive is very easy to operate, with an intuitive app or web interface, and a simple wireless thermostat control. Evohome is more complex, particularly with multi-zone systems, but our experience of the app and web interfaces, as well as the full colour in-home controller, it’s surprisingly easy to monitor and control.

What we’ve seen of Tado, OWL Intuition, Climote and Heat Genius suggests an easy-to-use experience both online and in-app. The wildcards here are the Salus iT500 and Cosy, about which there’s too little information to get a clear idea of how well they’ll perform. We’re looking forward to seeing Cosy’s demonstrations now they’ve achieved their Kickstarter goal.

Smart thermostats: How much money will I save?

Multi-room smart thermostats like Evohome, Heat Genius, OWL Intuition and Salus iT500 offer the greatest saving potentialMulti-room systems like Evohome, Heat Genius, OWL Intuition and Salus iT500 have the greatest potential for cutting your spending by heating only the rooms you need, but you could easily end up spending four or five times the cost of Hive, Nest, Climote or Tado on a four-bedroom home.

Learning systems such as Nest, Heat Genius and Tado could easily outsmart manual scheduling, especially by switching off when the house is unexpectedly empty. Our experience with Hive suggests you won’t always remember to turn off your heating if you’re out having a good time.

Nest, Heat Genius and Tado all learn to adapt to your daily schedule. On paper, that puts Heat Genius in the lead, since it’s not only the cheapest multi-zone heating system, it’s also a very smart learning system if you add motion sensors. Evohome will appeal to those with the most demanding multi-zone environments.

There’s also a certain smugness in knowing you can control your heating from anywhere in the world. As the most basic system, Hive owners will get least of this intangible benefit and those with smart systems like Nest, Heat Genius and Tado will get the most.

If you’re into a long-term pay-off, integrating solar power with OWL may take a decade to deliver its cost back, one day you’ll have the added smugness of knowing you’ve saved the planet and made some money. Don’t forget to check out our other top 10 energy saving tips.