Nest Learning Thermostat review

We review the latest smart thermostat from Nest, available to buy now, just in time for a delayed British winter.

Like the previous model, the third generation of Google-owned Nest Labs’s thermostat lets you control the heating in your home remotely from your phone and adjust your heating schedules.

New tricks up its sleeve include the ability to control the hot water as well as the central heating, a slimmer design, higher resolution screen and support for something called OpenTherm – which promises to save you money by burning gas intelligently.

So, does that really work? Can the new Nest thermostat really save you money? Here’s how we got on.


Nest 3rd gen: What’s the big deal?

As well as being super convenient, Nest’s learning thermostats keep track of your daily routine and learn to anticipate when you’re getting up in the morning and getting in from work.

The theory is that Nest will eventually know that you usually get home at around, say, 7:30pm when you’ll   crank up the heat to 28 degrees. Old school thermostats would have the boiler jump from cold to hot in the shortest time possible. The Nest rule of thumb is to slowly heat things up well ahead of your arrival, thereby using less energy.

You can also set schedules from your phone or the Nest website and disable these if you’re going to be away on holiday. There’s also a freeze protection setting which will see your home be heated to a minimum of 7°C at all times.

Nest has recently released the third version of its learning thermostat, following the launch of the second generation – the first one to officially go on sale in the UK – back in 2014.


Nest 3rd gen learning thermostat vs 2nd gen: What’s new?

The main party trick of the new Nest thermostat is that it’ll let you warm the water along with your radiators, depending on the type of boiler you have. This sees Nest catching up with the competition – rival heating systems Tado, Climote and British Gas’s Hive have let users control the water temperature for some time now. Nest might be late to the how water party, but it’s better to be late than never.

Other improvements include a feature called Farsight. This basically lets your thermostat double as a fancy clock. This motion powered feature will see the Nest’s dormant screen ghosting into life if it detects you waving at it from across the room. By default, the screen will display an analogue clock, but you can change in the settings so that it gives you a quick update on the temperature.

Most of the changes are cosmetic; compared to the second-gen thermostat this new model is slimmer and comes with a screen that’s both bigger and sharper; 2.8-inches, 480×480 compared to the 1.75-inch, 320×320 screen of the previous edition.

That slimmer profile hides dual-band WiFi antennas, which is pretty much the norm for most WiFi-enabled devices these days but, again, it’s another first for Nest’s thermostat range. Practically, this means if you’re setting this up in the same room as a router or an adapter that uses the 5GHz band you can make use of that faster, less congested channel. We’ll touch more on the implications of this in the Installation and Set-Up section.

Aside from the WiFi boost, it’s unclear what other new gubbins Nest has crammed into the innards. According to the Nest site, there’s no indication if this new version improves on the touted 10-12 per cent reduction in heating bills.

We do know that this new device is compatible with something called OpenTherm, which we’ll touch on later.

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Nest 3rd gen learning thermostat: Design

Who knew that something as dull as a thermostat could be so sexy? Seriously though, it’s worth waxing lyrical about the look and feel of Nest’s new ‘stat because, well, it looks great. If you’re going to drop £179 (plus installation) on something that’s going to sit in your home it may as well be eye catching.

The screen features a retroflective layer that gives the device a neat cat’s eyes-type effect that just adds to the polished lustre of the brushed metal mantle.

You may already know that Nest Labs was co-founded by former Apple employees Matt Rogers and Tony Fadell. Fadell was previously senior vice president of Apple’s iPod Division; it’s perhaps no surprise then that it feels like some of that company’s magic, not least the iPod clickwheel-style of the thermostat itself, has rubbed off here. But the weighty heft of the device, the convex glass bulge of the screen and the accompanying ‘click’ sound designed to mimic precision mechanics turning suggest that the designers have taken cues from luxury pocketwatch makers more than Apple, or anyone else.

The plastic wall mount that comes in the box is a little less snazzy, but it’s optional; if you’d prefer to have your Nest appearing on the wall without a white trim around it you can. Alternatively, you can shell out for a Nest Stand (£40, sold separately) if you’d rather have your device sitting on a bookshelf, coffee table or mantlepiece.


Nest 3rd gen: Installation and Set-Up

Installation typically costs an extra £50 on top of the standard price for a 3rd gen Nest thermostat (£199) for a grand total of £249. Pro tip: Nest says that if you buy the hardware and the installation together, you’ll save a bit on VAT under the UK’s Green Deal tax incentive programme.

To be honest, unless you’re a qualified electrician or you really really know what you’re doing, it’s best to pay for an installation.

In the box you get something called a Nest Heat Link; this sits in between the thermostat and the boiler. Nest strongly recommends that you let a professional handle this part of the process, as the Heat Link uses 230V mains electricity. Again, unless you know what you’re doing here, it’s best to let the pros handle it.

As for where you want your thermostat to live, you’ve basically got three options; you can replace your existing one, hang it up somewhere else on a wall or mount it on the aforementioned Stand.

The latter two options mean you’ll have to power the ‘stat from the mains as you’ll not be drawing any juice from your home wiring. We opted to set our thermostat up on a Nest Stand, as there wasn’t really anywhere we fancied hanging it and we preferred having it close to hand on top of a shelving unit instead of suspended on a wall.

Once the Heat Link is up and running and you’ve decided where to house your thermostat, the rest of the set-up process is dunce-proof. Simply connect the Nest to your WiFi network and follow the on-screen instructions.

This is a bit of a faff – especially if you’ve picked a long and tough-to-crack password – as you have to hunt and peck through the alphabet by turning and clicking the wheel. Thankfully, you should only have to do this once/every time you move house/change password.

Combined with our professional installer doing all of the complicated and life-threatening-in-the-hands-of-the-unqualified work, everything took about 40 minutes to get up and running.


Nest 3rd gen learning thermostat: How easy is it to use?

Design-wise, the Nest is a gorgeous, beautiful bit of kit – but as we’ve said, cycling through the many menus and sub-menus on that circular screen can be a bit of a task.

For this reason, if you want to do anything fiddly, like set up and change schedules, you’re really better off using the apps.

The Schedule feature lets you easily create schedules by plotting desires temperature and start and end times on an XY-axis. These can be easily tweaked on a whim, so you can still have the heat coming on in those weeks and months approaching spring, while reducing the temperature.

You can also handily copy and paste heating schedules, making it easy to create a schedule for Monday-Friday while having different schedules for the weekend, or however it is you divide your time up.

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Nest’s Auto-Schedule and Auto-Away features attempt to get a handle on your normal routine and switch off the heating when you’re not at home, respectively. Both of these measures are designed to save you money by not heating up an empty house.

During set-up you can invite your other family members and housemates to create Nest Accounts and therefore gain access to the schedules and settings. This simultaneously frees them from the restrictions of your tyrannical heating plan and also means that the thermostat will organically build up a more natural pattern of people’s comings and goings.

There’s a couple of issues to bear in mind here though. Auto-Away relies on the thermostat’s sensors to detect whether anyone’s at home. Unlike other smart home systems that use GPS information to trigger actions, Nest’s motion sensors will perform a sweep of the room to determine whether or not you’re home. If it thinks that you’re away, it’ll eventually shut the heating off. You can manually override this or disable Auto-Away from the settings if you don’t want to use it at all.

If you really want to use GPS data to trigger Nest actions then there’s third party workarounds like IFTTT (If This Then That) and Skylark, but as they’re not official solutions, Nest can’t help you if things start going awry with your schedules.


What is OpenTherm and how does Nest’s hot water feature work?

Earlier we mentioned OpenTherm. On paper, this claims to allow for smarter communications between the boiler and the Nest thermostat, to the point where if you’ve got an OpenTherm boiler, it will burn the exact amount of gas needed in order to reach your desired temperature.

Or so Nest says – the combi boiler we’re using for this review isn’t OpenTherm-certified, so we’re not able to provide any more information on this ourselves.

While we’re on the subject of combi boilers, we should point out that this type of boiler is designed to give you hot water on demand. This means that there’s no need to schedule water temperatures via Nest or make use of a hot water boost function.

That said, OpenTherm-certified combi boilers may let you set hot water temperatures between 40°C and 65°C but again, for the reasons we’ve just explained, there’s no scope for boost action.

For those people with non-combi type boilers, the hot water feature of the new 3rd gen Nest thermostat will by default heat your water between 6-8am and from 4-10pm.

Nest and OpenTherm representatives have been unable to give us an average saving, owing to the vast number of boilers on the market and the upgrade paths of each customer; if you were to move from an older non-condensing boiler to a condensing model (which are on average 25 per cent more efficient) the savings would be greater than if you were to switch to another non-condensing type.


Can you actually save money with Nest’s learning thermostat?

As we’ve argued in the past,consumers won’t be able to really start making savings calculations until we get smart meters installed in our homes. These will tell you exactly how much you’re burning through in real, financial terms and (hopefully) will allow you to be a little cleverer about your energy use. Nest isn’t a smart meter.

What it does do is flash up a little green leaf whenever you’ve turned the temperature down to an energy-saving level. In terms of temperature, Nest generally defines this as anything 16.5°C or cooler, a goal which might be achievable in spring and autumn months, but let’s be honest, that won’t even touch the sides for most homes in winter.

As Nest learns a little more about your heating habits the green leaf parameters will shift, which will see you challenged to pick temperatures a few degrees lower to those which you’re used to.

Diving into the History page of the app will give you an overview of the last ten days of energy use. Because we’re environmentally conscious goody two-shoeses, you can see that we’ve aced the green leaf target for most of January. Go us.

Whatever your feelings on the climate change debate are, the rule of thumb is if you see the green leaf, you should be saving money. Nest says that turning the heating down by one degree represents a saving of 5 per cent on heating bills.

Results of a US-based trial from last year also claimed that a Nest learning thermostat will save you around 10-12 per cent on bills versus the savings you’d get with a typical thermostat.

It should go without saying that weather varies greatly across the United States and the relevance of such findings for potential UK buyers should be taken with a pinch of salt.

Or, as Nest’s own white paper says:

“It’s important to note that thermostat savings in any given home can vary significantly from these averages due to differences in how people used their prior thermostat and how they use their Nest Learning Thermostat, as well as due to occupancy patterns, housing characteristics, heating and cooling equipment, and climate.”

You should note that this trial was undertaken with Nest’s 2nd gen thermostat as well. At the time of writing, Nest hasn’t been able to tell us whether or not its latest device improves on this.

That’s not to say that it won’t save you money; by sheer virtue of the fact that it endeavours to not burn any gas if you’re not at home it will save you something.

While Nest sends you a regular monthly report, this currently only tells you how long you heated your home for, in hours. This could be useful, depending on how you’re billed by your supplier, but it doesn’t break down any costs for you.

The real issue is, we can’t say how much until we get our government-approved™ smart meters. Until then, we’ll have to wait for our energy provider’s statements and compare them with those from last year to find out how much we’ve actually saved.


Verdict: You will save sexily with Nest – we just can’t say how much

Nest’s third-gen thermostat is a beautifully designed appliance that affords you a great degree of convenience. As for how much money it can save you, that depends on how fastidious you are as much as Nest’s own scheduling algorithms.

If you’ve got an OpenTherm-branded boiler then there’s potential for even greater savings, although we unfortunately can’t currently tell you how great and as we found out, not every boiler out there will meet this specification.

Given that loft insulation can save you on average £140/year and condensing boilers are 25 per cent more efficient than the older non-condensing ones, there’s some more immediate savings to be had, if you’ve nto already explored these routes.

The lack of a location-assisted away setting, while surmountable via third party options, is a bit of a drawback. If this is a dealbreaker, you might want to reach for something like Tado or Hive.

That said, if you’re the type of person who often finds themselves working late and you’re living in a house where there’s plenty of people coming and going at all hours of the day, you and your co-habitants will no doubt appreciate the freedom Nest offers.