Competition: Nest Learning Thermostat: Black Box Analysis

Since Nest is the only competing product you don't have to take a loan in the bank to own (well, maybe just a small loan), it was interesting to get a first hand experience with it. So, I bought it and installed next to one of DZ sensors.

I am reluctant to talk to my competition because the amount of information they can extract out of my questions significantly exceeds the amount of information they can extract of my most honest answers to their most detailed questions. --GT

Well, the experience was definitely interesting.

The Excellent

The most impressive (from usability standpoint) thing about the installation process is how they implemented pairing the device with the online account. I created the account (took a split second) and several seconds later, when I turned  to face the thermostat (less than a meter away), it was already displaying the message asking whether I want to associate it with the account I just created. Under the wraps, it is pretty simple to someone in the trade (they probably matched the WAN IP to serial number and account name to the IP it was created from), but nevertheless very impressive. Definitely karma bonus for creativity.

The Good

• No-brainer installation for someone with hands growing out of shoulders.
• It was impressive that it correctly determined wiring.
• It was really simple to configure it to work with the existing system (those who know how many variations of thermostat wiring and systems are out there will be definitely impressed by this).
• Upon connecting to WiFi, the device immediately downloaded the update.
• There's just a few seconds latency between the device and the web app.
• Control algorithm seems to be smarter than just a simple hysteresis loop, will see how smart later.

The Neutral

• Temperature displayed is the setpoint temperature, not the actual temperature.
• Both setpoint and actual temperature display resolution is 1°F and 0.5°C, this is not sufficient for some conditions (good example: the room with little air getting to it, while the other room next to the HVAC unit gets more than it bargained for). Making this happen, though, will destroy the "Apple" aesthetics.
• Not sure how successful will be WiFi connection when a DHCP server is not present. Too lazy to try, hope they did something smart.
• Initially, I thought that the device was blind as a bat and doesn't sense presence right, but then realized that it's just doing it in its own way.

The Bad

• It was quite painful to enter a 21 character passphrase for the wireless network.
• It took two reboots and about 10 minutes to download and install the update.
• There is no indication of how close the thermostat is to calling - itchy fingers *will* try to bump the thermostat if they feel too hot or too cold.
• Settings change sensitivity is, unexpectedly, extremely high compared to setpoint change sensitivity - the latter is less than 1:1, and the former is almost trigger fast. Uncomfortable, and is a violation of the principle of least astonishment.
• There doesn't seem to be a way to change the hysteresis from the default. This will cause short cycling for smaller rooms, and stale air for bigger.
• The maximum "away" temperature setting for cooling mode is just 90°F. Folks, this is not enough for hot climates - I *work* comfortably at 90°F, and won't be afraid to set the away temperature to 100°F on the second floor.
• Actual temperature is not easily visible over the "grill" (and for °C, good luck trying to distinguish "22.⁵" and "22°").
• Web app and mobile app don't honor the °C measurement unit for ambient temperature. While we're at that, why don't they display other data available from Weather Underground (which is their data source)? (The weather is displayed as a background picture)
• Standard 18 AWG thermostat wire doesn't fit into the base, had to use thinner wire. I had a patch panel for wiring so it wasn't a problem, but good luck doing this if all you have is the cable sticking out of the wall.

The Ugly

• Fingerprints all over the glass.
• Guess what two users tried to do (independently from each other) when asked to change the setpoint on iPad app. Correct, they tried to replicate the circular movement that it takes to change the temperature on the actual device. Instead, they were presented with ancient up and down arrows. Come on, folks, *I* did better than that, gesture detection is not that complicated.
• Entering several spaces in the passphrase was most excruciating. Hint to Nest developers: it is possible to use all that nice space between the alphabet and done/cancel/backspace symbols that you already have, and plant some spacebars right there. Yes, in every shift mode. Won't hurt. Took quite a while to figure out that those spaces are currently just for decoration and aren't functional.
• And it was completely infuriating when after spending about two minutes of entering the passphrase the thermostat happily reported "failed to connect" (it was a transient failure) and... displayed the EMPTY prompt again.
• Let me just say this... Don't even try to use their webapp on a mobile phone. Their "beta" is not Google's "beta". More like "alpha". At $250 plus shipping a pop.
• Where is my Android app? Right here: Nest Mobile. Pretty basic, though, nothing to write home about.

The Verdict

Short version: Meh.

Long version:

• Hardware looks to be decent (though, just like I suspected, there's not much stainless steel, it's mostly plastic).
• Embedded software (on the thermostat itself) is perfect as far as usability is concerned, but passable as far as climate control is concerned (no comments about learning ability, that'll be covered later).
• Web front end is definitely in alpha stage. Let's hope that they are planning to advance it, or at least make it work right on a wider variety of devices.

Applicability

All the information above is pertinent to model Diamond-1.10, display software ver. 1.0.4, base ver. 3.5.2/1.1, as of January 5 2012.

Competition: Nest Learning Thermostat: Teardown

Sparkfun published a nice article about Nest teardown.

I wonder if the battery is replaceable other than by "contacting technical support" (update: from the link below - no, it is not replaceable).

As usual, comments are as useful as the article if not more.

C Wire-less Setup

In particular, here's a link to an article describing a subtle problem: Undocumented Nest incompatibility with single-stage wiring. Incidentally, all three of three HVAC units I have do *not* have the C wire. Here's what Nest has to say:

• When Nest needs a common "C" wire
• Should my B wire go in Nest’s O/B connector or in the common (C) connector? (this one is actually very important because it is a thinly veiled liability disclaimer ("If a common wire is inserted into any connector other than C, it may blow a fuse in the HVAC system and damage Nest"). Be sure that your B wire is not actually a C wire. It would be nice if they provided a way to determine this for sure using something as simple as a multimeter, more on this later.
• Power Specifications for the Nest Learning Thermostat
• Does Nest need a common wire?
• What do Nest's wiring errors mean?

Would it be a regular dumb thermostat with nothing but dry contacts, I'd fiddle with wires. With this device, I guess I'd go for their installation service if there is anything out of ordinary. Or spend more time digging the actual wire layout. By the way, DIY installation video doesn't even hint at this problem, which makes me think there'll be lots of pissed off overconfident DIY dudes with attitude killing their Nest and blaming the manufacturer for that. Their Returns & Cancellations page is mum about what is gonna happen if the thermostat comes back dead because of customer's fault, it'll be interesting to see how this gets handled.

Afterthought: Multi-zone Setup

I missed the How does Nest work if I have multiple Nest Learning Thermostats in the same home? article when I was writing the original review. Stark contrast with DZ approach: one relatively expensive control panel per user (optional) and lots of dirt cheap sensors vs. many expensive control panels. The other side of the equation, though, is Apple aesthetics, learning capability and ability for everyone to control the temperature vs. powerful, though not quite below-average-IQ-friendly scheduler and unlimited tinkerability (at high price of your involvement, of course). These products are for totally different markets, that's for sure.

Early Access: DZ on Android

Effective immediately, Android remote control application is available.

Visit the forum to find out more.

Competition: Nest Learning Thermostat

Brent brought the news about Nest Learning Thermostat. Mandatory review follows.

THE GOOD

• Supposedly good design and excellent workmanship.
• Equipment check that is eventually done right. I wonder why nobody thought of that before, usually this information is buried deeply inside technical manuals (and good luck if you lose one).
• Subtle interface cues to what is going on (I did this first almost two years ago, though).
• Remote control. Guess this is the new fad.
• Outside weather awareness.
• Supposedly helps you saving energy. Gives you energy usage statistics.
• Multiple thermostats working together.
• Massive amount of documentation (go to support site and click on the arrow next to the "search" box without entering any search terms).

And to finish the panegyrics, here is a welcome thought:

I wonder if the largest effect might be getting people to voluntarily interact with the thermostat at all, thereby thinking about their HVAC more. The fact is that most of us only think about our heating and cooling systems when they’re not working. If we start thinking about them when they are, we could save more energy. The nest is so appealing to interact with that it might shade that in the energy-saving direction.

If for nothing else, creators of Nest deserve high praise for this effect alone.

THE BAD

First and foremost, this is just a banal thermostat. With it, you inherit all problems inherent to banal thermostats (a comprehensive explanation is at our FAQ). The main issue, again, is:

Thermostat makes itself happy. It doesn't care about you. It is not where you are.

In other words, it didn't cross the fundamental border between where the sensor is and where the control unit is.

Other than that...

• Apple lovers will be, no doubt, excited by this device and the promise of "Apple quality". Everyone else might have a doubt (for example, when they say "stainless steel", I ask "how thick?". Need to touch it to actually confirm this statement).
• Needs to be installed where it has a constant (or at least frequent) view of you. And where are thermostats normally located? Correct, in the corridor, next to the air return. Good luck making the thermostat aware of you in a big house, or if it is located in a place you normally don't walk through often.
• Remote control with no fuss means external server the thermostat is talking to. Keeping it secure requires you having the account at it, and sending *your* data to it. Oh, by the way, prepare to deal with it. This is the only way one can do it without the fuss. We're doing the same. So will everyone else.
• Outside weather awareness means external sensor. Or always-on internet access and temperature resolution down to city or so. Which is pretty much useless to you.
• Speaking of which, support site search... Let's just say it could be better.
• Even though zoning support is advertised, it will be limited for one simple reason: zoning systems need much more granular signal than just on/off.
• iPhone and iPad only? Again? Where's my Android app?

THE UGLY

• I want to buy this product on Newegg or Amazon. I don't want to engage in a process as complex as house refinancing, and be subjected to individual pricing based on how much I am apparently willing to cash out.
• Did I forget to mention? I want to know the price up front.
• A blog without an RSS or Atom feed? Is a clog.
• Customer reviews for a product that is not being publicly sold? That's not a good smell in my book.
• "Invitation only" procurement model suggests that not everything is as shiny as the outside ring of Nest thermostat, and it may not be as production ready as they want us to believe.
• The knee-jerk reaction of my son to seeing the demo was: "One button? Again? I'm sick of one button!". Couldn't agree more. Two quotations come to mind immediately:
  • If you create a system that any idiot can use, then only idiots will find it useful.
  • Make things as simple as possible, but not simpler.

THE UNKNOWN

Their documentation is very good, and lots of unknowns have already been resolved. However, there are fundamental questions that are left unanswered:

• The price for the device $249 plus shipping;
• The price for Nest account;
• What they do with your data;
• Do they allow you to take it away (like others do);
• Does the device and infrastructure support open protocols, or it is as closed as everything Apple ever did?

And if the account turns out to be free, but you can't take your data out? Then you are the product being sold.

UPDATE (2011/11/02): Price was published.
UPDATE (2011/12/06): BGR published a short review. Comments deliver.

Early Access: SwitchDamper

For years, DZ was able to control modulating dampers.

It seems, however, that bang-bang dampers still have their place, hence, SwitchDamper was added to Subversion and will become a part of the next release.

Now you can use DZ to control any HVAC actuator that is controlled by a switch. This includes, in particular, but not limited to:

• existing open/close dampers normally controlled by 24VAC;
• electric heaters that are configured as auxiliary heaters in a complex zoned system;
• hydronic, geothermal and steam system valves.