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Smart thermostats aren't new -- Netatmo has been selling its Philippe Starck-designed model since 2014, for example. But if you're trying to manage the heating for a whole house or office building, one central thermostat can leave you over- or under-heating some rooms. Netatmo's new Smart Radiator Valve gives you individual controls.
The promise is that, by heating different rooms appropriately, you can control your heating more efficiently and save money while staying warm.
At home, that means you can have the bathroom nice and toasty in the morning when you use it, then not waste money heating it for the rest of the day; heat the lounge but not the spare room in the evening, and only warm up a bedroom just before you go to sleep. In the office, you can keep the lobby warm enough to deal with cold draughts from the front door without overheating the main office, and only heat the conference room during working hours.
Instead of running around turning radiators up and down by hand, Netatmo's automated solution relies on a combination of remote control thermostatic valves; a smartphone and web app; individually-configurable room temperatures and schedules; and an algorithm that turns the heating on just in time based on the external temperature.
The Valve works with a range of heating systems: boilers, heat pumps, wood-burning systems and even flats with shared thermostats, as long as they drive radiators with hot water in. If you don't already have thermostatic valves on your radiator you'll need to get a plumber to replace the manual valves first; the Valve is designed to replace existing thermostatic valves. If you do, the valves are easy to fit; there's a small tool to help you find which of the handful of adapters included is the right size and thread gauge, and you just unscrew the controller from your existing valve and put the stylish Netatmo one on in its place.
It shows the room temperature -- not just the usual 1-5 numbers of a radiator valve that leave you to guess how high you need to turn it. You can turn it by hand to change that, although the big advantage is the ability to do that from your phone -- especially if the valve is behind a sofa or bookcase, the way it is in most of our rooms. Manual temperature changes last for three hours, although you can change that default.
The e-ink display, the actuator to turn the valve and the wireless control don't use a lot of power; Netatmo says the batteries will last two years.
Fitting the Smart Thermostat is also fairly straightforward as long as you're comfortable with wiring. You can connect it directly to the boiler using the wireless relay that comes with the thermostat, or replace the thermostat that's wired to a central heating controller. Any heating engineer can also fit the thermostat for you (the list of official installers on the Netatmo is rather short).
The thermostat has the same sleek white and plexiglass design, with an e-ink display, and you can choose from five decals if you want to give it a hint of colour, but mostly you'll use the smartphone and web apps to control it. There's even a Windows Phone app, although it only controls the thermostat, not the radiator valves.
Also handy is the integration with Apple HomeKit, Alexa, and Google Home, which lets you ask your phone or smart speaker to turn the temperature up or down if the automatic setting isn't right. (HomeKit needs you to have an Apple TV or iPad in the house if you want the Smart Thermostat to work when you're out of the house with your iPhone.)
Some smart thermostats are a little too smart, especially for multiple rooms and a range of occupants, but the Netatmo system takes a much more straightforward approach. You can tell it when you get up, leave the house, come home and go to bed to get an automatic schedule. Or you can individually set the temperature you want in each room for different times of the day, and then you can turn the temperature up or down from the app if you're cold or warm. You can choose whether the valves can only turn off the boiler when radiators reach the set temperature, or whether they can also turn the boiler on if the temperature drops. And after the thermostat has tracked how long it takes your rooms to warm up and cool down (which determines how effective the insulation is), it will offer to start turning the heat on a little early to reach the temperature you want gradually, again taking the external temperature into account.
That could prove more efficient than running the heating full power to get to the temperature you've set, or you might find you can set a lower temperature and still have the room be as warm as you want it to be at a certain time. If a window is open or the oven is on in the kitchen, the Valve turns the radiator off to save money.
If there's something unusual about any of your rooms (say the Smart Thermostat is wired to your central heating controller and is in a position that's much warmer or cooler than the rest of the building), you can program an offset to the temperature measured.
For extra precision, if you have a Netatmo weather station as well, the system uses the actual temperature outside rather than a forecast for the local area (for a London suburb, we found that slightly more accurate and it could make a significant difference in rural areas where the temperature varies more throughout the area).
Simply not overheating rooms, or heating rooms you're not using, will save you money, and a calculator on the Netatmo site lets you see how quickly you'll cover the cost of the equipment.
There are 'frost-guard' and 'away' settings (7℃ and 12℃) and the beauty of a smart system is that you can turn them on from your phone if you have to go away on an unexpected business trip (or the office party goes on for much later than you planned). You can also set when you want your normal schedule to resume, thereby avoiding coming back to a room that's much colder than usual.
The Netatmo app and website show internal and external temperature, as well as what you've set the temperature to be (so you can see how well the controls do at delivering the temperature you want without running the heating more than necessary) and how much of the time the boiler is on for. Not only will that information help settle office arguments about how hot or cold the room really is, but once you start measuring temperature and heating, you can start to make informed decisions about how to manage it.
Instead of turning the heating on and off at set times, you can leave the heating on, but only have the boiler and radiators running when they need to be on to deliver the temperature -- no more wasting money by heating the office on an unexpectedly warm day only to have people opening windows and turning on fans to get comfortable.
The Smart Radiator Valve is pricey, at £69.99 for each radiator. You'll also need either the £149 Smart Thermostat or a relay that connects directly to your boiler; fortunately, Netatmo's Smart Thermostat is rather cheaper than other smart home thermostats. The per room settings could be easier to work with: rather than individual schedules for each room, there's a single schedule with the option of different temperatures for different rooms. Whether you'll save money depends on how carefully you control your heating already, but this is definitely more convenient and gives you far more control.