With the recent news of a new version of the smart thermostat Nest coming out, I figured I should finally write up what it has been like living with the first version of the product since last November, when mine arrived.
Overall, it's been a great little tool, smart in lots of smart ways and dumb in just a very few and eons ahead of similar products I've used. Back in the early 2000s, I spent some time in my first house trying to automate everything. I used x10 to control my lights and set up schedules to turn lights on and off at certain times and I bought a programmable thermostat in the hopes of not only saving energy but also allowing me to wake up to a pre-warmed house in the winter.
I recall how quickly my adoration with home automation faded when I decided to stay up 15 minutes later than normal only to have the entire downstairs lighting shut off to pitch black per the schedule I created. I also remember spending hours programming the thermostat with complicated weekday versus weekend programs, and how after a couple months I just gave up and used it like a normal thermostat that sat at fixed temperatures.
When I heard about the Nest, I immediately ordered one and patiently waited the months until it arrived. It came with a free professional installation that would be scheduled a couple weeks later, but I decided to try it myself and like my last house it was pretty easy to do and 20 minutes after I started, everything was running and it was downloading software updates from wifi (pictured above).
After about a week of using the thermostat to adjust temps (fun bonus: cranking up the heat on a cold December morning from the comfort of your bed, using the Nest iPhone app), it started to realize our patterns and follow them (I rarely have to run the iPhone app these days). It was a nice change from the hours of programming I did in the past and it just seemed to work for my family, realizing that we woke up around 7am most days, went to sleep around 11pm, and started shutting itself off whenever we were gone for the day. After about a month, I went onto the Nest.com website to check the schedule and it only required a minor amount of tweaking to follow a perfect pattern.
Let me say straight up that the motion sensor in it is pretty amazing. It realizes when no one has been home for a couple hours and sets your thermostat to auto-away mode, saving energy by going to prescribed temp extremes (colder than normal in winter, warmer than normal in summer). I've never had it go to auto-away while I was home working even though it's in a different room. I should also say that if I had a normal office job, the Nest would be doing an even better job. I'm at home about five days a week so it doesn't get tripped into away mode as often as typical houses where most people are gone during the daytime weekday hours.
It's hard to say what the bottom line is on energy savings for me. I don't watch our electric bills super closely and our bill includes charges for water too (which usage fluctuates wildly), making quantifying the post-Nest world a bit tougher, but I do know the system goes into auto-away mode reliably several times a week and it's been great to set the whole system to away mode when we've been on vacation. Having a vacant house heated and air conditioned is a lot like running your lawn sprinklers during a rainstorm, a total waste of money. It's also great to have the iPhone/web connections to control it even though I don't need it very often. I remember bringing up the phone app and taking the house out of away mode at the airport when we landed from a vacation, and arriving to a cool house in the summer an hour later.
About the only downsides are how it sometimes acts a bit too eager to please. You might have a dinner party and turn on the air conditioning a few degrees cooler than normal to keep guests comfortable, and the thermostat is supposed to ignore one-off moments like this, but I found it slightly adjusting itself at odd times that reflected short term changes. This also happened when I left the country for a week while the rest of my family stayed behind, introducing a new schedule where I wasn't home all week in my home office that had to be adjusted later when I went back to my old schedule.
Apart from those minor schedule nits, the Nest has been great, warming the house on winter mornings, shutting down each night about an hour before we typically go to sleep, following our coming and going patterns appropriately and being completely controllable in real time from either the web or our phones (and also by the nice weighty dial on the unit itself) if we need to change things. I won't be buying a new one (for the same reasons Marco states here the software updates make getting a new one unnecessary) but I can wholeheartedly recommend it to all my friends as a neat way to save a bit of energy and turn a dumb appliance like your heating and air conditioning into an automatically configured smart object that works with your own patterns of behavior.