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A thermostat that learns? Three months with the Nest

The launch hype is over. What's left? A capable-but-geeky learning thermostat.

A thermostat that learns? Three months with the Nest

It has been close to a year since the Nest "learning" thermostat was introduced to the public, bringing us one step closer to that elusive home of the future. Founded by the former senior VP of Apple's iPod division, Tony Fadell, along with his partner Matt Rogers, Nest Labs set out to create what is essentially the iPod of the thermostat world. The round, user-friendly device was initially met with excellent reviews, but were these based in reality or were they the result of some Apple-like hype?

I like to think of myself as somewhat of a thermostat nerd. (Listen, it doesn't sound very exciting because it's not, but I like them). I am fascinated by thermostats and their usability, but I also don't like to spend too much money on them—unless the extra cost is worth it. Friends and Twitter followers have long asked me to evaluate higher-end thermostats, and I'm always examining the thermostats at other people's houses. So when I finally had the opportunity to install a Nest, I jumped at it.

Now that I've been using the Nest for several months, I have a pretty good feel for its strengths and weaknesses—at least compared to what is typically available on the market. Is the Nest really worth the $250 it costs to obtain one, just so you can have a fancier way of turning the temperature up and down? I think so—especially if you're the "convenience oriented" type (that's PC for "lazy").

What's so great about the Nest anyway?

General usability

The usability of the device as "just" a thermostat is extremely straightforward, and it's the first thing you deal with after installation. Overall, it's pretty good—as you've likely already seen, the thermostat itself is a round wheel, similar to the original iPod's moving click wheel, but in thermostat form. The device has a backlit screen that comes on when you mess with it, or whenever you pass by it (if you have that setting turned on). I like to have it light up when I walk by, because it allows me to see the current setting at an easy glance as I'm on my way to the fridge or the living room.

The background color of the Nest turns blue when the air conditioning is running, and an orangey reddish color when the heat is running. When nothing is running at all, the background is black and the text is white. Just walking up to it and turning the dial will wake it up and allow you to turn the temperature up or down. If that's all you ever wanted to do with your thermostat, then that's really all you need to know.

More importantly, the device can connect to your WiFi network, which lets it perform a number of valuable functions. For one, it can update its own software over WiFi, allowing the company to issue bug fixes and even add features (if they should feel so inclined). Since the Nest's original release in October of 2011, there have been 10 software updates seeded wirelessly to users' Nests, most of which were released in May of 2012.

That in itself is a handy feature, but the WiFi functionality serves another purposes to us lazy geeks: the ability to see stats and make changes to our settings remotely. Nest comes with a Web app, as well as an app for iPhone, iPad, and Android—the functionality of which I'll get to in another section of this review.

But the Nest's interface can do a lot more. In addition to turning the thermostat, you can also "click" it by pressing down on it; this brings up a plethora of other features that you can scroll and click through. If you want to set yourself to "away" (more detail on this later), you can do so by clicking once and turning to the away setting. You can also enter your address when you first set up the device so it can bring in the local weather. This is useful for its energy statistics, because it can tell you whether the day's weather affected your thermostat use. You can also set up your account there and view/change the Nest's learned schedule.

Learning features

In fact, the Nest's headline feature is its capability to learn. The device learns what you like, when you like it—there is no schedule to program, only a schedule to live. If you want the thermostat set to a certain temperature when you get home from work, set it that way for several days and the Nest will eventually figure it out. Do you like the temperature to be at 75°F at 6pm on Monday through Thursday, but 73°F at 3pm on Fridays and 80°F at 4pm on Saturdays? The Nest will figure that out too, as long as you give it a few data points to work from.

I found that it generally takes about a week or so to train a Nest to conform to your schedule. That's not too bad, especially if you consider the trade-off in the time it typically takes you to figure out how to program—and reprogram, in the case of a schedule change—your older thermostat. There is no reprogramming involved with the Nest. If your schedule or preferences change, you can just start training it to your new schedule and it'll be there in a few days. But if you need a one-off temperature change—say you're home "sick" for the day but you're really playing the new Call of Duty—it won't throw off your schedule. Individual temperature changes won't force the whole schedule to change unless you make that change consistently for several days in some kind of pattern. And even then, it will eventually switch back if you somehow end up switching back to your old schedule.

Other cool features

The Nest learns things besides your schedule, too. One of my favorite features is its time estimates for when it will reach the temperature that you've requested. Nest's materials state over and over that you can't get to a cooler (or warmer, depending on the season) temperature by setting it to extremes, so don't do it—instead, it tries to tell you that it will reach 73°F in, say, 25 minutes. It takes several weeks for the Nest to learn how fast it takes to heat or cool your place to the desired temperature, but I have found that after a few weeks, the time estimates are extremely accurate. I have set the temperature and taken note of the time estimate many times over the past several months, while also setting a timer on my phone, and found the times to be almost exactly on point, adding a certain comforting layer of information to your temperature choices. (Just don't try to explain that to the people you live with, who may think that setting the thermostat to 55°F will result in a cooler home faster. They just don't listen.)

2+ hours? Maybe I'll bump the temperature a little bit to save the whales.
2+ hours? Maybe I'll bump the temperature a little bit to save the whales.

In fact, setting your Nest to extreme temperatures isn't just useless—it's actually a bad idea. Since the Nest learns from the temperatures that you set, it could learn that you actually want it to be 55°F all the time (when you actually want it to be 70°). Luckily, the Nest seems to discourage this behavior—perhaps even indirectly—because of the time estimates; when someone sets the temperature to significantly lower than it is currently, they may not feel very satisfied once the Nest tells them it'll take 5+ hours to get there, forcing them to reconsider their temperature choices.

There's also the away and auto-away modes. While the Nest allows you the ability to manually set yourself to away—say if you're going on vacation or even just going away for the weekend—it can also detect when there hasn't been any activity nearby and will automatically determine that you're not home. The Nest has a motion detector that allows it to do this, and you can set the maximum and minimum temperatures you'd like to maintain through either the Nest's website or on the Nest itself.

For example, I have my maximum temperature set to 80°F (I have cats, so I don't want them to boil to death) and the minimum set to 60°F; this temperature range applies to both regular "away" mode and auto-away. If the Nest hasn't seen me in a few hours, it will just set itself to auto-away and won't turn on again until 1) it sees me again, 2) it hits one of my preset thresholds, or 3) I manually change it remotely. Upon viewing your energy history (again, more on this later), you can definitely see where the benefits of auto-away kick in. The Nest tells you which days were affected by which factors, and being set to auto-away (so the thermostat saves its energy) appears often in my timeline.

My only beef with auto-away mode is when you are home, but you just don't pass by the Nest very often in the course of navigating your place. I'm often not on the same floor as my one and only thermostat, so it sets me to auto-away more often than actually needed. This can be solved by adding another Nest (as they can talk to one another and adjust themselves accordingly), but naturally, that costs another $250.

And if you live in a home with people you don't trust—kids, or your shady brother-in-law—you can lock the Nest with a PIN as well so that no one can change the temperature. You can only set the PIN on your physical device (not the website), and if you're the owner of the Nest, you don't have to worry much about losing the PIN either, as long as the account is associated with your e-mail address. You can reset it if necessary, and the process isn't any more painful than resetting your password on a website.

Finally, the Nest learns any and all adjustments you make. Whether you're making adjustments from the website a thousand miles away, from your iPhone in bed, or while standing right in front of it, you can train it to whatever patterns you have in your normal life.

Channel Ars Technica