LOL. I just had to tweet that just now.

/r/askscience is tackling this question.
http://www.reddit.com/r/askscience/comments/mgwj4/which_is_more_efficient_keeping_my_house_at_a/

Here's a teardown of the thermostat for those that are into circuit pr0n:

http://www.sparkfun.com/tutorials/334

Mine have arrived. Installation will be this weekend, when I've got time to clean, prep, and paint the wall around the thermostat.

Yeah, not a teardown by someone with much of an eye for detail (no chips looked up for example) but nice pics nonetheless.

The strange optical thing facing backwards is an optical mouse sensor, used to pick up the rotation of the dial. That idea came to me when I was trying to work out how to make a standard IR quadrature encoder lower power...

Cute. The author claims there's Zigbee in there. We've got a "smart meter" on our house that speaks Zigbee, and I've got a not terribly clever battery-powered display that gives me data reported by the meter. Can my Nest (eventually) patch into this?

Can't really comment on that, apart from saying that Zigbee is a standards nightmare. Everyone appears to be running different layer2's over it...

This, and the licensing issues for an "open" standard map it even more irritating.

Woah. Though I can't help wondering whether it still comes out ahead if you factor in the carbon footprint of making an optical mouse sensor in the first place...

Peter

If you're trying to factor in components' carbon footprint, I imagine the energy saved over the lifetime of using the Nest (relative to a dumb thermostat) blows away the cost of the extra components.

Also, I imagine that Hugo's design will never fail during the service lifetime of a Nest thermostat. There are plenty of other things more likely to fail first, like the battery.

So has anyone got one working on a UK system yet ???

Cheers

Cris

Initial thoughts after installation:

- Of all the different cans of paint in the garage, none of them are the shade of green on the wall where the downstairs thermostat goes. This after I made a trip to Home Depot to get all the assorted bits and parts to fix up the paint job.

- So screw it, I mounted the Nests using the supplied mounting plate. Despite the videos to the contrary, it helps to have your own tools, particularly a needle-nose pliers and a proper screwdriver. For the upstairs thermostat, where there's wood behind the drywall, none of the included screws did the job, so I ended up having to use the longer screws that held in the original thermostat. (The non-Nest screws I used have larger screwheads than the proper Nest screws. This made it more difficult for the thermostat to fit onto its mounting plate. I had to push uncomfortably hard on it to get it to seat properly.)

- My wife **hates** the look of the Nest. Unlike the original white Honeywell box, the silvery Nest thing is quite obtrusive (to her); she feels like it's watching her. (It does remind me a bit of HAL 9000.)

- Setup is straightforward, but the WiFi support seems a bit wonky. I have my DrayTek base station upstairs and an Asus AP downstairs. For the Nest closer to my Asus, I typed my WiFi password twice and it never worked. I unplugged the Asus, forcing it to sync up with the DrayTek and it worked and appears to be continuing to work. It's the same password, so I don't know what's going on there. All our other devices seem to roam happily from one to the other. Only the Nest thermostat has had any issues.

- Pairing the thermostat with your account at nest.com is easy. The thermostat displays a code that you type into your browser. But... the first one never required me to type this in. Instead, nest.com's page, on my laptop, said something like "hey, I see a thermostat nearby!" and foomp, all paired up. How did that work? I have no idea. Maybe both were emerging to the Internet sharing the same IP address via my router and nest.com noticed this. I'm not entirely sure. Somebody clearly tried to be very clever here.

- The thermostats seem to be keen to save power by going to sleep and not phoning home. Maybe. Screen shot below.



- Check my network settings? Sure. Touching the thermostat causes it to check in and it's back online again. Otherwise, it's offline and there's no way (yet?) to queue a command for the thermostat when it comes back. Also, there's no way in the network settings to know which base station the thermostat's paired itself with. It would be nice for it to display the MAC address of the base station it's paired with so I can attempt to debug this.

- Programming the thermostat via the web interface is surprisingly klunky. They clearly want you to let the thing learn by itself.

- The feature I'm already missing from my $40 Honeywell thermostats is the ability to have it heat and cool without bugging me to switch modes. On the Honeywell, you can effectively program ranges that change over the day. So far as I can tell, the only range support for the Nest thermostat disables the learning / scheduling business altogether. If I could make one feature request, it would be to fix this. (This time of year, in Houston, temperatures swing from the 40's to the 80's, Farenheit, over the course of any given week, so it would be deeply annoying to be constantly flipping the thermostat back and forth from heat to cool to heat.) Never mind I'm probably one of three people in the world who actually figured out how to have my Honeywell actually do this and the Honeywell UI is totally garbage. At least it did the job.

- iPhone application, available today. Android application? Sorry, that will be out "in December". I'd be curious to know whether these apps speak directly to the thermostats or whether they're just pretty versions of the web page, where all communication between you and your thermostats is going through nest.com.

- This also raises something of a privacy concern, since Nest Incorporated clearly knows your schedule. I've read over their privacy statement, and it's pretty good. The only glaring flaw is that they claim they store my WiFi password on their servers. That's bad. My WiFi password should never physically leave my house. (It's different from every other password in my life, so the compromise of it wouldn't be particularly catastrophic for me, but it might be for others.)


Anyway, give me a few weeks and we'll see how well the learning works and whether the lack of auto-switching from heat to cool is a serious issue or not.

Thanks for the initial feedback. It's a bit disappointing to hear that there may be an issue with having to flip it between heat and cool modes. This is one of the primary reasons I wanted one.

At least it has the ability to be updated software wise to improve over time.

Looking forward to your further insights and thoughts about the Nest.

Sounds like a version 1 product. Most of the kinks will likely eventually get worked out if they ever make it to version 2

Incidentally, now that it's daytime, I'm not having these online/offline problems. Perhaps the thermostats were assuming "it's late, so I'll go to sleep and recharge my battery".

Or maybe.. "I'm new, my battery is low, I'll just sit and charge for a spell." ?

Curiosity: I've got my thermostats set to "turn on when approached", presumably leveraging the motion sensor. They only turn on, however, when I click them. Could there be a faulty motion sensor? How could I tell?

I read that part of the privacy statement differently. Its pretty specific that it's the thermostat itself that is storing the key.

The lower power objectives weren't for green reasons (pretty much the whole thing is "green" in that respect; a typical HVAC relay's pull-in current is at least double what the thermostat takes). It has to be low power because the whole thing runs from batteries.

Optical mouse chips are cheap, because they're made in such volume. They're pretty much 128x128 CMOS cameras with very cheap lenses

Likely bingo (though I don't know for sure)

That uses the short-range proximity sensor vs the PIR. Mine sometimes doesn't turn on either, but I've not worked out what the reason is. I suspect software updates will fix the glitches over time...

Here's the full WiFi language:
I'd say the text is somewhat ambiguous on *where* this stuff is being stored. Given that it's all "password protected", that would tend to imply they're talking about the server side, since there are no passwords in the thermostat.

As to the proximity sensor, I've discovered mine works, but only if I wave my hand a few inches in front of it. At 12 inches or more, it never wakes up.

As to the charging and network unavailability, I've noticed a pattern that they're unavailable at night and available during the day. I hope that the learning process can figure out that I'm more likely to want to dork with my thermostats at night, after my kid's in bed.

With a heating only, radiator based system, even if it does work on an electrical level, would it actually do anything that my bog standard 'stat doesn't?

We've only just turned our central heating on, it's been off since April. Even then, it's on for 2 hours in the morning and 4 in the evening.

Amusement du jour: got home at the Nest had an announcement on the screen that it had detected insufficient movement over the past few days to be able to confidently run its "auto-away" algorithm. (It's positioned in a central location. If it has roughly the same hardware as a standard security system motion sensor, it should be able to figure out when we're around.)

At this point, the #1 missing feature, so far as I can tell, are nerdy things. I'd like the display to be able to show me the various sensors as they're working. I'd also like the web interface to be able to graph things over time, like temperature or humidity. I assume the data is in there, somewhere.

Pretty sure the technical info screen will show you ALS, prox and PIR sensor readings (scroll waaaaaaay down). It used to, at any rate.

Yeah, I'd like humidity, temperature, etc logs too. I remember very early on (the office was a garage) building an arduino-based wifi temp/humidity/light/pressure monitor and loving seeing the humidity drop when the AC came on, etc.

The sensors I want are definitely nerdy: i still want a bluetooth prox sensor, because honestly, my or my wife's cellphone being there are the only triggers that really matter. Too bad leaving bluetooth enabled on the iPhone has an actual battery impact.

Yes, now that I know it's in there, I want to be able to get it out and graph it.

Seriously, it's so little power that it's in the noise. Leave it on, along with wifi. WiFi used to sleep at sub 1mA when associated to an access point, I believe Bluetooth was about 0.25mA.

If you assume that you have 100 hours standby with both wifi and bluetooth off, you'd have about 92 hours with both of them on. In the real world, where you do leave your house (hence wifi will be lower power) it's even less impact.

Really though, you should be using geofences to determine whether you're at home or not...

using geofences assumes something running on the devices and actively pushing info. i haven't put iOS 5 on either of our iPhones yet and am still waiting on an untethered jailbreak (or a different dam to burst first)

Yes, it needs something on the device, but it doesn't need to be running.

Even iOS4 apps could be woken by the OS when geofences were crossed. Pick the right level of granularity and it didn't even need to use GPS - it just got woken by the baseband when the local cells list (which is updated every ~2.5 seconds when the baseband wakes up to check for pages)... ie, basically zero extra power over standby.

Not that I've seen any geofencing app that works properly apart from reminders on iOS5, though... and that uses GPS