Life with a Nest smart thermostat: week one

nest energy history photo
Screen capture Nest

When I wrote about Fitbit as a tool to encourage walking, I used the analogy of "smart" thermostats as a gateway to energy conservation. I confess I am not exactly an unbiased observer in this debate—alongside my Fitbit, I managed to wrangle a Nest "learning thermostat" over the holidays, and have been geeking out ever since.

Given the legitimate question marks over whether such gadgetry is really worth the money, I thought it best to document my experiences here. This is the first in a series of occasional posts sharing my experiences with the Nest. First, a little background.

Our home
We live in a 1930s, two story, 2,200 square foot house in Durham, North Carolina. Our heating is a two-stage natural gas furnace, and cooling is central AC. The system is separated into two zones, with the Nest controlling the downstairs and a regular programmable thermostat controlling the upstairs for now (we may upgrade if the Nest proves itself worthy). While the house is pretty darned leaky we have been slowly improving the building envelope. Recent upgrades include air sealing doors, windows, piping and baseboards; the addition of floor insulation; insulating and air sealing the attic access, as well as general, gradual energy efficiency replacements like LED lighting and efficient appliances. Because many of these upgrades were recent (I was caulking a leaky electrical outlet only yesterday...) I may never be able to offer definitive numbers on what, if any, energy savings the Nest delivers.

Our schedule
We have a pretty irregular schedule, meaning the Nest is already a step up from the cheap programmable thermostat we had before. Because my wife works odd hours on different days, and because I am home some days, and out others, the simple split of weekdays and weekends was next to useless for controlling daytime temperature. We previously programmed in a slight setback during the day on weekdays, but not big enough to make the home uncomfortable if someone was home. Now we're able to set and fine-tune a schedule for each specific day of the week to account for who is home, who is not, and when they are likely to return.

web app schedule imageNest/Screen capture

The installation of the Nest couldn't have been easier. In fact, it was kind of a delight to see a product for which installation has been so carefully thought through. Included in the packet were a small screwdriver, cover plates (in case you need to cover up ugly holes left by the old thermostat), drywall self-anchoring screws as well as a set of labels to clearly mark all wires from your old thermostat. Nest also offered up a very smart, simple tip to make sure things stay on track: take a photograph of your existing thermostat's wiring before you remove it so you can refer to it later. Really, the only problems we ran into were a) the really ugly patching job we had to do beneath the existing thermostat (not Nest's fault), and b) we were mildly concerned that drywall screws would not work in a 1930s plaster wall. But following Nest's instructions, we pre-drilled some holes and the screws worked just fine. Here's a video of the installation process according to Nest, and it matches my experiences.

Set-up was even easier than installation. Once we linked it to wifi, it warned me that a couple of specific wires hadn't been connected properly. I consulted my photo of previous wiring for reference (see above), popped off the cover, readjusted the wiring. Then we simply answered a few questions about our home and heating system, set up an account online with my laptop, and we were good to go. Here, again, is a video from Nest on the set up process. It was every bit as easy as promised.

The first week
One of the big selling points of the Nest is its "learning" capability, meaning in theory you don't really have to program it. Instead, you simply adjust the temperature as you go along and, over time, Nest learns what temperatures you do and don't like and constructs a schedule for you.

To be honest, this feature is a mixed bag for me—someone who is motivated enough to program his thermostat. Rather than simply adjusting temperatures in real time, I found myself setting the schedule day-by-day—which made a nice change from trying to anticipate the whole week. I could check in with my wife about when she'd be leaving and when she'd be home, and then combine her and my timetable for a (hopefully!) more efficient schedule. The interface for scheduling temperature changes is intuitive and versatile, allowing you to schedule as many temperature changes as you wish.

The appearance of a little Leaf icon when you choose a more efficient temperature is a nice, if simplistic, touch—and I can see it being a motivator to turn the heat down. And the ability to visit your energy history online to see how often the furnace is running, and when it is kicking into stage 2 heating, is a useful way to evaluate your impact. I am looking forward to seeing the monthly emailed versions. (It would be nice if the history also showed outside temperature and other variables to give you a better idea of what is and isn't working.)

energy report nest leafs imageNest/Screen capture

The mobile app has also been great, allowing me to check the temperature while away from home and turn the heat up before we head home. Not only does it provide flexibility, but I also find it reassuring to know I have access—meaning I can be a little "braver" in programming a set back.

When you first fire up the thermostat, some of Nest's much-touted features are not immediately available. These include auto-away (it can turn the heating down when it sense nobody is home), time-to-temperature (it learns how long it takes to heat/cool your home depending on weather conditions, and adjusts scheduling accordingly), and sunblock (it knows if it is in direct sun, and adjusts its temperature reading for a more accurate figure). After the first week, Nest informs you that these features are ready and you can get playing with them.

As someone who already pays attention to their energy use, I find auto-away to be a bit of a gimmick and have not yet enabled it. Not only am I likely to set the temperature manually anyway, but I don't like coming home to an unheated house—so would prefer that Nest not pull any surprises on me. That said, I can see that if you lived in a house that heats up/cools down quickly, you weren't likely to remember to adjust the thermostat yourself, and you regularly left for longer periods of time, auto-away might be an energy saver.

nest time to temperature imageNest/Screen capture

What I'm more excited about, however, is the time-to-temperature feature (see above). My Nest now tells me how long it will take to reach a particular temperature, which discourages that silly habit of turning the thermostat higher or lower than you really need it in the mistaken belief you'll get to your desired temperature quicker. Not only this, but because Nest learns the interactions between your home and the outside weather conditions, you can schedule your temperature changes for when you actually want them—rather than either scheduling the heat to turn on half an hour before you need to "just in case", or alternatively waking up cold when it's excessively frosty outside.

Initial verdict
It's obviously too soon to provide a thorough review or have any idea of if I am really saving money. As I mentioned above, because the arrival of the "smart" Nest coincided with several "dumb" home improvements too (Lloyd would have killed me otherwise!), I may never know exactly how much Nest is impacting my energy consumption. That said, my initial impression is a fairly important one: Nest has already changed how much I think about my heating and cooling. I remain convinced that Nest's most overlooked function, alongside automating energy efficient choices like scheduling or even using a fan, is providing a regular, intuitive and easy-to-access/hard to ignore feedback loop as to how our lifestyle choices impact our energy consumption. And even if that's all it does, that's a pretty valuable step forward.

I'll be writing some more about life with the Nest in the near future, but please do post questions/comments/things you'd like explored in the comments below. In the meantime, to continue the theme of "dumb" versus "smart" homes that we've covered many times before, it's an encouraging sign that alongside fancy fans, remote-controlled LED bulbs and electric car chargers, Nest is also hawking something much simpler and potentially more important on its website:

nest blanket photoNest/Screen capture

I told you Nest was a gateway drug to conservation...

Tags: Air Conditioning | Energy Efficiency | Heating


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