A month with Nest's latest smart thermostat

Nest's programmable thermostat has just turned four, and the company marked the anniversary with the debut of its third-generation device. Four years ago, thermostats were still boring blocks stuck to your wall and while programming them was already possible, it was always a painful process. Once you'd fixed your temperature schedule with an endless collection of up- and down-arrow keypresses for Sunday through Monday, that selection remained fixed, with the very thought of changing the schedule leading to cold sweats. Typical configurable settings included a schedule for cool, heat and occasionally vacation mode. I've lived with one for ages and it has run faithfully, always following the schedule I made when I first set it up many seasons ago. I've coveted the Nest thermostat since launch and so, when I was recently offered an opportunity to use the newest version at home I jumped at the chance to see if it would really make a noticeable impact on my world.

I live in Canada and my hometown of Ottawa gets pretty damn hot and muggy in the summer, and bitterly cold in the winter. With a yearly temperature swing from minus 18 degrees Fahrenheit to the mid-90s without factoring in humidity, we worry and talk an awful lot about the weather. But because of this swing, we're constantly cooling or heating our homes to combat the elements, which means energy cost is always a concern. One of Nest's selling points is that the device can purportedly save you 15 percent yearly on cooling and 10 to 12 percent on your heating bills. Unfortunately, the new Nest arrived in the few weeks a year where days and nights are generally comfortable here, so the savings discussion won't factor into this story too much. I'd really need to compare the upcoming winter to last year's to get an idea of how it fares when heating.

Nest Thermostat

Before I received the unit, the Nest team suggested I use a compatibility widget on its website to ensure my current heating system wouldn't run into any issues during my install. In a pinch, Nest can direct you to professional installers nearby if you're not up to the challenge. My installation was relatively simple: After shutting off power to the furnace from the breaker box, I only needed to strip four wires (your mileage may vary), pull them through the hole in the base, use the base's built-in level to make sure it went on the wall nicely and then screw it down tightly. I also opted to use the trim plate to hide the marks left by the previous thermostat package, although it definitely looks better without. Also, if your toolbox isn't exactly overflowing with gear, the Nest package includes a small, high-quality screwdriver to help get the job done -- this isn't your typical IKEA Allen key. Once plugged in and powered up, I set up my Nest account, entering WiFi info and a few home details right from the device. With that out of the way I just had to use it, and wait for it to learn my home's heating and cooling patterns.

We've settled into a rhythm over these last four weeks and it does genuinely make the right choices most of the time. When I got up at 6AM in the early days after the install, I'd typically spin the dial to warm things up to 67 degrees; now it has that figured out for me. When I leave the house and set the Nest to "away," it doesn't seem to affect my schedule, which is good because I was initially worried those gaps when I was gone would wreck the Nest's "learning." I also appreciate the ability to change the temperature from my phone if I'm feeling cold while watching a film in the basement.

One other handy feature I found is that I can set a PIN to lock others out from manually changing the temperature outside of a range I preset. Some members of the household have been known to cool the house to the mid-60s on warm days. But as an example when things don't run perfectly, I was recently up really, really early and fired up the furnace at 3:30AM. Unfortunately, it seems the Nest took that morning to heart, because I was woken the next morning by the furnace starting at about the same time, suggesting it was adapting to my "new" schedule. You can manually edit blips like this out, of course, although I was surprised that a one-time event affected my schedule so drastically.

Nest Thermostat

While my experience so far has been positive, I did run into an odd situation after the Nest had been mostly set to off for a couple weeks because the weather was perfect. It turns out that in some four-wire installations like mine, the thermostat's charge can run down. Unlike traditional units that use little to no power or run using AA batteries, the Nest needs more juice to power its display, WiFi and so on. How it gets a charge is through oscillating the furnace by turning it on and off really quickly to charge (when running full-time, it charges constantly). Typically, while it charges in this mode, your furnace won't care and neither will you, but in my case it resulted in a buzzing sound I could hear from a couple feet away. I spoke to a Nest technician about this and he suggested I install a C-wire (a common wire that delivers 24V to the Nest all the time from your furnace), which would get rid of the issue. As a bonus in rare situations like mine, Nest will reimburse some or all of the cost to have that work done. In my case, the problem apparently corrected itself before I even had a chance to install a C-wire; it hasn't made that buzzing noise since.

The Nest's physical updates in this iteration are minimal, with a larger, more pixel-dense display leading the charge ahead of a less obtrusive housing. The display size has been bumped up to 2.08 inches from the previous gen's 1.75 and the housing is a scant five-hundredths of an inch thinner. The display's pixel density also gets a bump to 229 ppi, which is about 25 percent higher than the last gen.

Ultimately, though, you'd be unlikely to notice these changes if the Nest were swapped out while you weren't home, but then again, some functionality improvements might catch your eye. The thermostat now features something called Farsight, which uses the larger display to show more info now that it's easier to actually see from a distance. It also wakes up when it catches movement from much further away (up to 20 feet), instead of requiring someone to be within a few feet. I keep my Farsight mode set to an analog clock, but it will alternatively display the time or target temperature if you choose. This feature isn't very useful to me because my thermostat is mounted on a wall I don't spend much time looking at, but I do notice the time flash on as I come down the stairs.

Nest Thermostat

Day to day, who notices their thermostat? Nobody. But I quickly found that something to which I never gave a second thought rapidly became a fun diversion. What temperature is the house now? Does it know I'm away? Is it learning my schedule? It will even remind me when the furnace filter needs changing, something I forget to do and that really affects heating and cooling. I can see the benefit to my lifestyle without even factoring in the savings yet.

Still, that's not to say it's perfect. It's not always as smart as promised, and the price is still high at $249. I also think that remote temperature probes to help balance winter heat and summer cooling would be handy; heck an enhanced Nest Protect could even help out here. Even better might be control over airflow in the house based on where you are. Watching a film? No problem, we'll just heat the basement and once you head up to bed the warm follows you there -- and while it's at it, why not shut off the lights, too? Ultimately, the Nest does seem to get it mostly right: I'm a big fan of the convenience plus the fact that I may reap some financial reward through energy savings adds a bonus. But more than that, it's one of the first smart home products I've lived with that isn't solving a problem that doesn't exist. The Nest's such a solid improvement over my old thermostat in every possible way, that my biggest question leaving this month of testing isn't should I keep it, but rather why did I wait so long to try one?