Nest 3rd Gen Thermostat

Nest
claims that its smart thermostat is an easy way of saving money on your future
heating bills. It has an attractive design and is easy to operate, but the
immediate cost might put some off. After living with the device for a year, our
results showed that the thermostat saved us energy usage, but the difference
you'll see will vary based on your house and heating habits. 
For •	Attractive design and finish 
•	Great mobile app 
•	Very simple to operate 
•	Learns and adapts with use 
Against •	No zonal heating control 
•	Functionality relies on good placement 
•	Best installed by a professional

Nest made some pretty grand claims about its smart thermostat when it was first announced. The company claimed that, through a more intelligent heating system, its thermostat could reduce your energy consumption by as much as 10% and hence save you money. 

We've lived with the thermostat for a year now, and we've got the data to work out whether there's any truth to these claims. 

Before it got into the business of making security cameras like the Nest Cam IQ and Nest Cam Outdoor, the smart home company was first and foremost about one thing: heating. 

The Nest Thermostat was the company's first product, before it got into security cameras like the  Nest Cam IQ and Nest Cam Outdoor, and it continues to be a very competitive and smartly designed thermostat, even if some of its functionality lags behind the competition in 2017.

While it is perfectly possible to control it with your phone, the Nest thermostat is clever enough that you'll soon stop bothering. Not only does it remember the various temperature settings you put it to throughout the day, using its built in motion sensor and GPS functionality of its app it will alter its program based on your schedule. 


Its not the perfect system, the lack of zonal controls means that you'll often end up heating empty rooms, but our year of use saved us just over 13.5% on our heating bill. There are a couple of caveats to this, though, so check out the Performance 

In the meantime, read on to learn how the £279 Nest Learning Thermostat works. 

There are two parts to the Nest Learning Thermostat. There's the thermostat itself, which can be fixed on the wall (in lieu of the existing thermostat for example) or displayed on an optional stand, which is sold separately. In the latter mode, you will need to put the Nest near to a power socket and within reach of your router (you will need Wi-Fi).

The other part is the heat link. This is the component that will control the boiler and communicate wirelessly with the thermostat.

We had the Nest Thermostat installed professionally, which the company recommends due to it needing to connect to some pretty high-voltage wires. Overall the installation took around an hour, and it was a fairly painless process for the installer to disconnect our old thermostat and install a Nest in its place. 

One household can have multiple zones, each with its own Nest thermostat and heat link, but most homes will probably have just the one thermostat. Nest doesn't currently offer any connected radiator valves to allow you to fine tune the temperature in various rooms. 

The thermostat's design is loosely similar to Apple iPod's click wheel. Not a surprise given that Nest was created by the same guy who designed the iPod more than a decade ago. It is made up of premium material (glass, brushed metal) and has a stylish design that certainly beats your standard thermostat in terms of looks.

The ring itself uses a rotate and press/click paradigm, similar to the iPod, to navigate the circular menu and enter data.

We really like the design of the thermostat. Turning a wheel to select a temperature is intuitive and satisfying, and although this control scheme struggles when youre doing something more complicated like inputting a Wi-Fi password, day to day operation rarely hits this level of complexity. 

The thermostats screen is a 24-bit colour LCD screen with a 480 x 480 pixel resolution, which is more than good enough to see everything you need to. 

The current temperature is displayed on the outer ring while the target temperature is shown in bold characters in the centre of the display. The sensor window contains temperature, humidity, light and activity sensors.

Once you've got the thermostat set up its time to start building a schedule. This can be done from the thermostat itself, but you'll have a much easier time if you use the app, which allows you to set temperatures for a specific day and them copy and paste them onto subsequent days of the week. 

We went for a pretty conservative 19 degrees centigrade for all of our heating periods. Although it would have been possible to set, say, 18 degrees in the morning and 21 in the evening, we don't imagine many people will care this much about this level of customisation. 

Of course, if you want to you can ignore this scheduling element entirely and simply let the thermostat learn as you use it. 


Using its array of sensors, Nest adapts to the user's habits, avoiding heating a home when it is empty, learning how long it takes for your system to heat up and even allowing you to generate energy reports.

You can tell that the Nest has sensed movement because its screen will light up as you walk by. In our first couple of weeks of use this worked to remind us to set the temperature to our preferred level throughout the day, but over time the Nest turned into a handy little clock in the hallway where we had it installed. 

The fact that we were able to have the Nest in our hallway allowed the thermostat to be much more effective than it would have been otherwise. In our home we were pretty much guaranteed to walk past the Nest as soon as we arrived, meaning it always had a pretty good idea of whether we were home or not. 

If, however, you've got your thermostat in a side room that you rarely visit, then the Nest can occasionally think the house is empty and turn off the heating. Turning on the GPS fencing in the app is needed to fix t

On more than one occasion the top floor was freezing cold because the Nest thermostat refused to turn on. It was a toasty 20 degrees centigrade downstairs, so why would it bother? 

We tried to mitigate this problem by turning all the radiators on the lower floor down and all the radiators upstairs up, but ultimately it couldn't fully solve the problem that the downstairs of our flat simply didn't get cold enough to kick the Nest into action. 

In the end we would set the Nest to a temperature that was a little higher than what we would have normally liked to make it turn on more often and heat the upstairs of our flat. It wasn't the perfect solution, but it helped. 

With a retail price of £279, you're ultimately buying the Nest Thermostat because you hope it will save you money in the long term. Nest claims that the thermostat will save you between 10 and 12% of your heating bill, but does this figure hold up under scrutiny?

After trying the thermostat out for a whole 12 months, we found that we used 13.5% less energy with the Nest than without, meaning that in our instance the thermostat would have paid for itself after around three years of use. 


The savings, then, came when we moved into spring, where the Nest turned our central heating off far earlier than we would have thought to ourselves. The biggest difference in energy usage for us came in January. 

That said, according to official Met Office data, 2016's winter was 2 degrees centigrade warmer than 2015, which might explain at least some of the decrease in energy usage. 

Every house and flat will be different, so its difficult to draw conclusive results from just a single sample, but we were pleasantly surprised. The fact that we were frugal with heating prior to getting the Nest, combined with the fact that it cant control heating on a room-by-room basis, meant that we thought our energy consumption would be flat, or even worse with the smart thermostat. 

However a reduction of 13.5% is promising, even if at least some of it can be explained by a warmer winter. 

Many have followed Google's lead in making similar smart thermostats, but its hard to deny that the simplicity of the Nests design means it continues to be an appealing product. 

Yes, smart heating might be niche, and it might take more than a couple of years for the thermostat to pay for itself, but there is a benefit there, if only a minor one. 

Ultimately the proof was in the pudding for us, and with a substantial reduction in energy consumption its hard to argue the Nest doesnt have something going for it. 

The Nest Learning Thermostat is well designed, simple to operate and packed with interesting design features. 

The way it learns your schedule is handy, but more impressive is the way its willing to automatically alter it when you don't need heating, meaning your never in a position of having to turn off your heating remotely because you've decided to stay out for the evening. 

Its brushed metallic finish means that it's one piece of kit you will be proud to adorn your lounge's wall. The user interface, the app and everything else simply worked.

Although Nest has gone on to expand its product range to include smart smoke alarms and security cameras, the Nest Thermostat is still a one product ecosystem, and that means that how well it works will massively depend on the layout of your home. 

Have it in a nice central location and the motion-sensing will work a treat, but you might find that the thermostat overestimates the temperature of your house and refuses to turn on despite some rooms being cold. 

Meanwhile, have it in a colder room that's more out of the way means the motion-sensing works less well. 

What you're getting for the price is a solidly designed and built piece of kit, but its utility will depend on your home. 

Given the high price, it would be unwise to buy the Nest Thermostat thinking that its going to pay for itself in the first year. By our calculations, a three year payoff period is much more likely, after which point you're essentially making profit on your purchase. 

If you're prepared to pay the cost, the Nest Thermostat is an intuitively designed and feature-packed piece of equipment, although the lack of zonal heating is a shame. The interface is a joy to use, and the thermostat looks good affixed to your wall.