Netatmo Smart Thermostat review: Control the heating with your phone

When we moved into a brand new home we thought that it would at least have a reasonable heating setup. How wrong we were. Instead a dual Siemens system - one thermostat for upstairs, one for downstairs - met us with disappointingly complex controls and no smart features whatsoever.

Enter Netatmo, the French smart home company, and its Smart Thermostat - our prospect to counter poor user experience and gain app-controllable heating and smart functionality once more. Hurrah.

As Google Nest users in a previous property, the idea of Netatmo was appealing on account of its simplicity and lower price. For many users you'll be able to self-install the thermostat where your previous model once sat (without necessarily needing to open up your boiler at all), or sit it in whichever room you choose on its mobile stand.

But with so many established smart thermostat systems already on the market - Nest, Hive, Tado, to name but three - does Netatmo's simpler battery-powered offering provide enough features to keep up?

What is the Netatmo Smart Thermostat?

In the box you'll get one Smart Thermostat with three AAA batteries, complete with wall-mounting plate and wall bracket (and a mobile mount if you're not mounting it to the wall), a separate mains-plug relay, plus the various screws, adhesives and a boiler adapter should these be needed for your setup.

The product does what it says on the tin: it's a thermostat, which can learn your home's heating characteristics over time, in order to apply its own (optional) smart heating algorithm, theoretically save you energy, and keep your home as warm as you wish.

There's an associated smart app, Netatmo Energy, for Apple iOS and Google Android, so you can wirelessly control and schedule your heating as you please. You - and your invitees - can then have full manual and scheduling control via phone or tablet. 

Self-installing the Netatmo Smart Thermostat

First thing's first, of course, you've got to get the Smart Thermostat to talk to your boiler and, most likely, swap out your existing thermostat. Our situation was a little more complex as we had to replace two thermostats with two Smart Thermostat products - so if you see differences in product pictures here, that's on account of their positions in our home.

An immediate pro and/or con - depending on how you see it - is that the Smart Thermostat is not mains powered. It runs on three AAA batteries instead. There's no way it can be mains powered either, so you'll need to keep spare batteries should the levels run low. The thermostat's display is only E Ink, however, which means it'll last for many months at a time.

From our point of view, especially in the scenario of swapping out our mains-powered thermostats, we see the battery power feature as a negative. It would be much easier to wire in the electrics - you'll have to tap one wire into a terminal block anyway when removing the old one, so wiring them into the product would actually be a simpler solution in our use case.

All this does mean the actual wiring of the Smart Thermostat is simple though. Once you've switched off the mains power, simply take the existing control wires from your current thermostat - here that'll be either a grey/black wire, along with the live wire (that's brown in the UK) - and pop one into each of the terminals inside the wall bracket plate (there's no polarity so no right or wrong way round to do this).

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Old thermostat

But that does point out the first thing you'll need to suss out: the neutral wire (blue) and any spare control wire will need to be housed in separate terminal block channels (which aren't provided - but they're cheap and easy to source).

The next issue is a more taxing one: the wall bracket requires screws to sit in each of its four corners, but standard UK back boxes are designed with two central screws, left and right. Furthermore the wall bracket has to sit on the provided mounting plate - which is a 13cm square, so it's quite massive - in order to remain rigid for the manual control functions to operate. The wall bracket is smaller than a standard UK back box so would otherwise 'float' into it and be inoperable without this plate affixed.

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Back box size

Resolving this was somewhat complex for us. In our setup we had to use oversize screws in our upstairs setup in order to meet the wooden joists far behind, meaning the angle was less than ideal and the screw heads a bit too large. In our downstairs setup it meant drilling new holes left and right through the wall bracket in order to be able to screw the product into the old thermostat's back box. Given the proximity to our lightswitch, too, the 13cm mounting plate proved slightly too wide, so it butts up against the switch and looks as though it's been fitted without consideration.

Note, however, that to this point we've not needed to go into our boiler to do any wiring at all. That's because the Smart Thermostat simply talks to a relay - which is plugged into a standard wall socket and talks to your Wi-Fi network - to send the signals between your app-controlling device, i.e. phone or tablet, and back to the thermostat in order to 'talk' to the boiler.

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Wireless relay

Note: if you have the Smart Modulating Thermostat product (which also controls hot water; the standard Smart Thermostat on review here does not) then you would need to wire in the control unit to the boiler as the Modulating product does not have any control wiring in the unit itself. We mention this as you can also setup the Smart Thermostat in this way. It's not a difficult task - it's a case of identifying certain wires in the boiler and swapping them with the provided radio relay so you can have a fully wireless setup.

Once you've fumbled the wall bracket onto the wall-mounting plate with the wires in place the thermostat's 'face' clips into place, holding the batteries within, and providing the ability to click each corner of the product to turn the heating up or down by half a degree Celsius. There's the option of adding a colour adhesive - in blue, yellow, green or orange - to add a lick of colour to an otherwise vanilla design, but we've gone simpler and left it plain. 

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Boiler wired radio install

On the flip side of the wall-mounting method, however, those who intend to simply mobile stand-mount the thermostat so it can be placed anywhere in their home, we think the battery-only option will make total sense because it means no trailing wires. Indeed, this might well be who the Netatmo option is best designed for.

How smart is the Netatmo Smart Thermostat?

Once the thermostat is setup and talking to all the right components, you'll more or less forget that it's even there. From here on in it's the app that's king. And this is where the Smart Thermostat earns its name. No more forgetting to turn the heating off downstairs - you can do it from bed at the touch of a button in the app. No more needing to crank the heating up manually either - you can do that from the comfort of the sofa by pulling your phone our of pocket and making the adjustments on screen.

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Netatmo Smart Thermostat app software review

Not that you'll be using the Netatmo as a manual system most of the time. The key is setting up schedules - housed in 'My Schedule' section within the app - that cover Monday through Sunday in whichever format you please.

Within a given schedule you can assign a given mode - Away and Forst Guard by default - or custom temperatures - Comfort, Night, Comfort+, Eco are the pre-sets - with the option of adding any number more as you please. As we're running a dual system we've also created custom saves for upstairs only and downstairs only controls - as to not waste heating a whole floor when it's unoccupied.

At the time of writing it's very much a work from home situation in the UK, so we've created schedules for At Work (a working week), At Home (our holiday period at home), and Away (when vacations and visiting the in-laws, etcetera, is plausible once more).

It isn't possible to pull custom temperatures from one existing schedule to another though - so we've had to create our upstairs and downstairs variations multiple times, which seems like a shortcoming in the app's thought process.

The app is otherwise easy to use, but does have a glitch here and there. It'll sometimes say it can't connect to the network, despite the signal being very strong throughout this household. Furthermore we've had intermittent issues with the relays disconnecting for no apparent reason and showing as '!' in the app, which means they aren't controllable until reconnected (a process which at first we thought required manual intervention but, typically speaking, just takes some patience - come back later to look and it should have reconnected by itself).

After one week of use the system will have a better understanding of your home and how it retains heat. Because the app has location data it can draw on local data for external temperature conditions, to get an understanding of insulation, heat retention, and heating time relative to that external temperature. Netatmo calls this PID, or Proportional-Integral-Derivative, which the app will alert you to being available - you can choose whether you want it activated or not.

Take note, however, that with PID in the driving seat your scheduling will be over-ruled. If the system knows it takes an hour longer to heat a room when it's freezing outside then it will kick the boiler in earlier. Great, right? Not if the boiler is adjacent to your bedroom and noisily fires up at 5am when you're trying to sleep. As such we've stuck with our own distinct schedules as preference, knowing when the heating will active on and off.

The idea is solid, the delivery for our scenario just hasn't always been perfect, but if you want the temperature setpoint to be reached by schedule time then the system is intelligent enough to perform this based on a variety of factors.

One feature we've been unable to test out is the addition of Netatmo's Smart Radiator Valves, which permit individual room/radiator control, allowing for even greater control over heating zones within your home. A great idea that we'll revisit once obtaining some for review.

What could the Netatmo Smart Thermostat improve upon?

Which brings us to where the Netatmo Smart Thermostat could improve. Yes, there's the installation quirks as outlined, there's the lack of mains wiring, there's the random relay disconnects we've experienced, but it's some of the smaller details where Netatmo can - and hopefully will - advance the system yet more.

Take Google Nest, for example, which can track user location and offer a smarter features using geolocation - this can recognise when you're coming home from work on the train, even if it's an hour earlier than usual on any given day, and fire the heating on accordingly. Netatmo's system doesn't offer anything quite like this, despite using GPS for your home's location.

The schedules, while customisable, also don't offer fine detail adjustment - we'd like to select the colour assigned to each custom temperature, for example, as that would help to comprehend the idea of a heat graph. But, no, Netatmo auto-assigns colours, often counter intuitively, so a big grey bar will represent the highest heat section in the evening when, in our mind, it should be a bright red or orange.

That said, given it's easy to setup and install by yourself and the scheduling is robust once setup as suits you, the Netatmo Smart Thermostat is a sound way to obtain app-controlled heating without a mountain of cost.