Nest Thermostat Review, Update #4

Update #6, Update #5, Update #4, Update #3, Update #2, Update #1, Install

A bit more about my Nest thermostat experiences.

On the weekend, I spoke with a support engineer from Nest regarding the issue I was having with one of the Nest units failing to properly read the room temperature. I swapped one of the thermostats with a thermostat from a different floor in our house and then monitored the results over the weekend. I noticed the same problem in the new location: the thermostat would regularly read a temperature that was 3 to 4 degrees warmer than the actual room temperature. As it doesn’t consistently exhibit the problem, it makes heating a room to a comfortable temperature somewhat challenging (and now that it’s 19F outside, I’d like it if it was a bit more on the mark).

I spoke again with the same support engineer from Nest today (Mark). He called back as promised at the telephone number I left with him. He agreed that it was the thermostat that had a problem and decided to ship me a new one immediately (overnight). As today was an “observed” holiday for most shipping companies in the USA, the new thermostat won’t ship till tomorrow.

Interesting tidbit is that the base of the device apparently has a serial number that is tied to the display and that they both must be returned at the same time when shipping a defective unit back to Nest.


When I arrived home this evening, my wife and I did our normal patterns. Go here, drop stuff off, etc. One of the places my wife walks nearly every evening takes her right by the Nest thermostat in a hallway on our first floor.

As we were sitting down for dinner about 30 minutes later I noted that the temperature seemed a bit cooler than normal in the kitchen so I walked over to the thermostat. “Auto away” had been activated. Arrgh. What’s odd (and annoying) is that the temperature should have been going to 69F starting at 5pm. At some point, it had decided that we were “away” and had never arrived home (I checked all of the schedules and everything seemed normal). I thought that there was some way to review the timings and choices it makes for that setting, but the “Energy” option on the thermostat reported “No data” for any of the recent days (I would have expected at least one day as I had moved the thermostat two days earlier).

UPDATE: Jan, 4, 2012: Ok the above happened AGAIN. I don’t know why I’d want AUTO AWAY to also DEACTIVATE the schedule? Seriously? Turn off learning. Turn off Auto-away. What’s left Nest?

So, I don’t know what to make of this new “feature.” Clearly, we were in the house and the auto away should have been deactivated by our presence (I thought?). We did not activate “away” mode manually either.


I definitely can’t give high marks to this product and wouldn’t recommend it right now. I know others are apparently having decent success, but until the kinks are worked out or they do a lot more explaining, I’d recommend anyone thinking about buying one to wait (maybe for v2 or a significant software upgrade).

If anyone from Nest is listening, please speak up!

(And anyone else with comments, questions, etc., feel free to leave them! I enjoy your comments and feedback and I know others are finding your comments very useful!)

I’ve created a new home for discussions about digital thermostats. Here’s a bit more information and here’s the site ( (And thanks for your help in getting it started!)


  1. I also have a Nest. My first Nest did not register the accurate temprature in the house. In the middle of the night, it would fall far below the 68 degrees it was set at. My baby woke me crying because she was cold. I turned up the heat and called Nest the next morning. The support person told me that he was not aware of an issue and suggested that I “restart” the unit. I did this and the Nest seemed to work fine for about 10 days. Then the same problem in the middle of the night…woke up to a crying baby because she was cold. Called support again because I have three other free standing thermostats in the house that were reading 4 to 4.5 degrees lower than what Nest was showing. I never had a variance with the 5 year old Honeywell thermostat. They asked if I could place one of the free standing thermometers next to the Nest. I not only put one Oregon Scientific thermostat I put (2) Oregon Scientific thermometers and a Lacross thermometer on a small table below the Nest. Two of the the three free standing thermometers showed exactly the same temp…the third was .5 off from the other two. The nest was 4 degrees off from the three. Support asked me to “hang a thermometer on the wall next to the Nest and then take pictures of the readings”….I told them I was not willing to do their R&D with out compensation….and I was not about to place a nail or tape on my wall that may do damage to the wall or paint. When pushing them and telling them I would blog and post about the shortcomings, they said they would send me a new Nest…they did…I went through the same set up…though this time the Nest was more interactive than the first one…alerting me that some of the learning had been completed. However, the Nest was reading 2 to 2.5 degrees higher than the three free standing thermometers. Support had mentioned (before they sent me the replacement) that the Nest could be picking up some wall temperature. To eliminate that possibility, I mounted it on one of the provided mounting plates, and I caulked the hole where the wires come through the wall…still the Nest is 2 to 3 degrees off from the free standing thermometers. Nest had also said that they had found that their technicians had found that the Nest is more accurate than most thermometers and thermostats on the market. I don’t know that I’m buying that…Like I said my Honeywell always matched the three thermostats within .5 degrees even when the 3 were located in three different areas of the house.

    I have yet to call Nest back since receiving the 2nd Nest. Has anyone had the same accuracy issues? I won’t say I’m disappointed….at least not yet….

    1. I’m glad I didn’t have to go through what you went through. Having a second working unit obviously made it a lot easier for me to troubleshoot with the Nest engineer. While I can believe that their thermostat may be more accurate than some others, a variance like I was seeing of 3-4F was way out of my threshold of acceptable error (and thankfully, Nest agrees). I wondered (speculated/guessed) if the unusual variances have something to do with the battery that needs to be kept charged to power the display (that the unit fails to consistently compensate for the the elevated temperature from a charging battery).

  2. I’m waiting to see what other’s say about the temp variance. I am not happy that it is several degrees off from every other device that I own. It may be more accurate…but the Oregon Scientific and Lacross thermostats are high end models. The Lacross is a weather station base and was over $100. So I find it hard to believe that the NEST is that much more accurate than the other leading brands of thermostats. I had some customer service issues with NEST as well…I spoke with the manager of the department and provided my feedback. I won’t address it here….as I feel that their deficiency’s will be addressed.

    I would love to hear what NEST has to say about the variences…I would think they are monitoring these blogs…..If they are not…shame on them.

    1. Right now, my impression is that they aren’t doing a good job of monitoring blogs, etc. It took several days for them even to respond to a simple tweet on Twitter.

      I’d say they completely underestimated the tech community and demands expected from a $250 thermostat.

  3. I’ve been considering replacing my Honeywell progammable t’stat with a Nest…but now I’m not so sure. I’m intrigued by the inaccuracy of the temperature sensor and the reponses/excuses offered up by Nest.
    Questions I have for Nest…
    1. What type of sensors are used in the Nest? Their marketing materials call out that three temp sensors are used to determine whether heat/cool is needed…three sensors(?) all in one t’stat, really?
    2. What is the rated accuracy, stability, and repeatability of the sensors and sensor circuitry?
    3. I’m curious to know what the A/D is for the sensors…not that it really matters – just curious. An 8-bit A/D would be fine for a residential product, but at $250 a whack I’d expect at least a 10-bit A/D.
    4. Where are the sensors located within the device relative to the circuit board, power supply, and battery. My hunch is the inaccurate readings may be due to misplaced sensors within the unit.

    1. Those are great questions Kevin! I’m not sure if anyone has done a tear-down (which wouldn’t answer all of your questions, but would be a start)?

    1. Nice. Thanks for the link Matt. As I’m not a computer engineer or “chip” guy (strictly software), that’s too much information! (I saw that people had tried to get access to any API, the protocol, etc., but have not had any reasonable luck yet).

  4. I would guess that the electronics in the stat is creating heat and they didn’t put the sensor in a spot that was clear of this. There is a lot of tech packed in that small package. If there is not a clear space vented to the exterior for the temp sensor, it will never read correctly.

  5. I’ve had my Nest for about 10 days. I would recommend waiting before buying one. Here are the issues I have:

    1) An advertised feature is that the Nest can predict how long it will take for the house to warm up when you increase the temperature setting, based on the outside temperature obtained through the net. So you would think that if you trained the unit each morning when you got up at 7AM, it would be smart enough to start warming things up at 6AM or whatever time was needed. Nope. So if you want to train it properly, you will need to get up at 6AM for a while or set the schedule manually, and it won’t adapt that time depending on the outside temperature.

    2) I go to bed after midnight, and the unit “learned” a time of 12:15 AM. I decided to move it back about an hour because the house cools off slowly. The web-based schedule editor was not able to accomplish this without deleting all the set points and re-adding them. You can’t move a point past midnight, and you can’t move a point past an existing point. I found numerous glitches and browser dependencies in the web site. It looks like a case of too-clever programmers and not enough QA people. (By the way, the schedule editor is flagged as Beta.)

    3) I was hoping to see some kind of performance data, such as a graph of house temperature or information about how long it took to heat up the house. Nothing yet.

    All of these problems are software based, so they might be fixed in the future. You might want to wait.

  6. Just another note about my Nest. The temp variance between my Oregon Scientific and Lacross weather stations and the NEST is now about a 1.3 to 1.8 variance…so I would have to think that the Nest is giving off heat that in return gives a false temperature read. I would really think that if Oregon Scientific and Lacross were 1 degree to 1.5 degrees off they would be out of business (as NEST stated that thier product was more accurate than the others)….I really don’t buy that the NEST is that MORE accurate…I can deal with a .5 degree variance, but anything over 1 degree in my book is not accepable….I really curious how many NEST owners have placed a thermometer near the NEST and compared the temperatures….I don’t think my issue is isolated.

  7. I forwarded a link to this Blog to NEST and suggested that they read it…if they haven’t already…there is an opportunity to address the concerns before it gets away from them…..

    1. I’ve tweeted my posts and included their account name (@Nest). They acknowledged an earlier post, but they’re too quiet honestly for a startup company. It will be interesting to see if they respond. :)

  8. My nest, in its 13th day, is a mixture of exciting potential but very disappointing behavior. It has still not learned the time-to-temp behavior of my system (which is perhaps slower than the Nest engineers tested for, a radiant system). It should turn the furnace on an hour or two before the set time, but still waits for the set time. It goes to auto-away, but does not detect our return. It gives “no usage” or nonsensical data in the energy panel. It does not keep as steady a temperature as the primitive Honeywell round thermostat it replaced. Some of its user interface design is goofy, too. Finally, I’m not getting any response to my support requests on their web page.

  9. I finally called Nest and spoke to a pleasant fellow. First off, it turns out the Nest does NOT anticipate a temperature set point. It will not turn on the furnace ahead of time. If you train it to go from the night setting of 60 to the daytime setting of 68 by turning it to 68 when you get up, it will always be 60 when you get up. Of course, it should have learned that you want it to be 68 when you get up, and it ought to have learned how to do it – how soon to crank up the heat given the characteristics of your system and house. If it were really smart, it would take into account the outside temperature and whether the sun is about to come out. In fact, it takes NOTHING into account, and it will be cold when you get out of bed.

    Here’s my more profound disappointment, however: I assumed the Nest was a “feed-forward” controller. Most thermostats use the classic feedback principle, reacting to the difference between the set temperature and the actual temperature. In other words, it waits until the the temperature is wrong, then does something about it. The temperature swings back and forth between too low and too high. A feed-forward controller estimates how much heat is being lost given the system characteristics (eminently learnable) and current (or foreseeable) outside conditions, and arranges for the furnace to replace it as it is lost, or even before it is lost. It monitors the actual temperature just to account for errors in its internal model of the system or unusual situations. The resulting temperature will be much steadier.

    The Nest has all the information and horsepower to be this more sophisticated type of controller, but under it’s pretty face, it is no smarter than a regular thermostat, perhaps less (even an old Honeywell device includes a crude but effective “anticipator” circuit to reduce temperature swings).

    In short, they launched the Nest before the engineers were ready with the code that would allow it to operate as a truly sophisticated controller, or even the simple code needed to anticipate set point changes.

    1. I’d guessed that it wasn’t doing any predictive stuff a few weeks ago.

      It’s good to get confirmation that that feature simply doesn’t exist. A big thanks to Curt for calling Nest to get some answers!

      Apparently, the “magic” of turning up the thermostat when I get home isn’t magic at all. I actually don’t want that. I want the house to be warm when I walk in the door (during the cold winter months). So, like I’ve already done, with every programmable thermostat, I create a set point based on a time when I expect to be home and a wild guess about how long it takes for the house to heat to that temperature. Now, of course, if I know (and think of it), that my schedule is going to be a bit different, I can adjust the thermostat(s) remotely. I bet I’ll forget more often than not though.

      I want their UI to have a feature where I can say, “68F” at 6pm. You figure out when to turn it up based on the outside temperature, etc. That seems like a much better way to save than traditional thermostats and very simple to do as it already claims to know how long it will take to reach a certain temperature.

      I’m also very disappointed by the auto-away functionality given that the device knows we’ve returned and could activate the programming again.

      While I realize that it’s a first generation product, it really feels like something where they took the Apple approach a bit too much: “We know what customers want.” In this case, I think they missed big time. they concentrated too much on the old school round thermostat and didn’t look at how people actually want to live.

  10. Quite right, David. I actually have Mr. Fadell’s original iPod right here. I think one of the lessons of Apple is that you need a raging a–hole to keep computer-oriented folks on their toes. (I’m an app-developer myself, so this is not a wild accusation.) While pretty and mostly good, even brilliant, the user-interface of the Nest has some breathtaking goofs – the varying sensitivity of the effect of twisting the dial as you move through different menu levels, for example. And this sort of thing: the Auto-away mode (according to the support person I spoke with) does not turn off immediately when you return, so yes – you can stand right in front of it when you get home, yet it will say you’re not home, and that is exactly what the engineers programmed it to do.

    1. I think their web site implies a lot of functionality that simply doesn’t exist. Their web site is a great marketing tool. It’s all so magical. Yet, the features we thought were there aren’t. And unfortunately, what many of us are finding is that what’s left isn’t very magical and is a bit frustrating right now.

  11. @ Curt and @ Aaron.You two are exactly right and perhaps NEST should hire you as consultants…perhaps the business model was to throw out a subpar product make a bunch of cash on the first release to help satisfy the venture capital guys and then let the smart techies respond with what does not work and what needs to work for the product to be viable. I am almost to the point where I may return the NEST and go back to the Honeywell…the Honeywell does not look as sexy…but it appears to have more functionality….I also thought the nest was supposed to monitor the humidity in the house….The lack of basics of the NEST to know when you walk by it and know that you “ARE HOME” was a big miss! Combine the lack of these features with tempratures that appears to not be very accurate…what do you have??

    They had better work on some firmware updates fast; otherwise other consumers will catch on to the findings found on this blog. Also the ap for the Iphone is pretty mundane if you ask me…where are the bells and whistles that warrant paying $250 for a thermostat?

    NEST Labs WHERE ARE YOU? you are welcome to jump in at any time!

  12. My Wife and child have been home for 45 minutes and the NEST is STILL in Away Mode….I turned it on from my Iphone…..I’m wondering how this feature works…does it know your home after you have been home for 20 minutes or an hour….or several hours?

    1. It won’t. You have to activate the thermostat again by changing the temperature or indicating your home (deactivating the “Away” feature).

  13. You guys are right in all the above posts. But to be honest, I’m happy with setting a schedule that warms the house before I get up in the morning, and saves energy overnight. Yes, I had that functionality at a lower price point before the Nest. But I didn’t have remote adjustments or the great looking hockey puck on my wall before.
    And I certainly didn’t have 3 units trying to “learn” at the same time!

    That said, keep it up fellas. I’m sure your (legitimate) complaints will only benefit me in the future.

  14. But it does! I get up at 4:00, but have Nest programmed to raise the temp from the overnight 64 to 71 at 3:30. No, it isn’t at 71 by 4:00, but it’s on it’s way and the chill is certainly gone. Same thing in reverse at night: bed at 8:00, but Nest programmed for 64 at 7:30.
    Manually/remotely adjust as needed intraday, and with learning “paused” it keeps my schedule perfectly.

  15. >First off, it turns out the Nest does NOT anticipate a temperature set point.

    LOL there are stats on the market now that can nail that trick for half the cost… Commercial controls have been doing it for 15 years or more now, and could be had for the same price.

    This thing is sounding more and more like snake oil. Not reading an accurate temp that the old HW round stat can, is troubling. Not meeting the grand expectations set will sink this thing in short order.

  16. I’ve had three running for about a month without any serious problems. One had a cold solder joint problem in the base but they overnighted a replacement, and of course, it only takes about five minutes to install a new one.

    All these “LOL my grandmother’s hand-wound thermostat does this” comments are missing the very important point that these things can and will be getting firmware updates… I’d stake money on the likelihood that the plan was to get basic functionality out there, then add features.

    1. @Mac — while I agree and fully expect updates to a device like this (especially given the issues some of us have experienced), many of us are experiencing bugs that shouldn’t be part of a “thermostat v1.” Appliances can’t have bad days and need to be rebooted. This device is in charge of controlling a possibly very large and expensive piece of equipment in most people’s homes (certainly does in my home). Grandma’s thermostat, while it didn’t support a firmware update, worked fine with a firm hand, and it worked. It did it’s one job well enough.

      That doesn’t mean I long for a simple analog thermostat. Anything but that! I’ve had several wireless thermostat in the past few years and have had programmable thermostats for a VERY long time. :) I want the simplicity in function and form that Grandma’s thermostat had. Nest has tried. They just haven’t nailed it on all accounts. They’re treating their customers like it’s a beta web application (which the web app is!), when for $250 — I expect final v1 product. Don’t you?

      Thanks for your comment!

  17. Aaron – we publish the web site Open4Energy – #1 site on the net for protecting consumers from energy scams – Google “energy scam” to validate

    We also publish a list of energy saving devices – a large section being Smart Thermostats – NEST is included – one of 9 – and there are more to be announced at CES I hear.

    Thank you for these comments – I will post a short excerpt (with credit) to this post – I believe it will help our readers.

    The big question I have – and I hope someone will find an answer is this. How much energy – heating or cooling – electricity or gas – is actually saved by having a NEST Smart thermostat versus a well adjusted digital thermostat – versus a wireless thermostat that does not have the NEST intelligence but can be Internet controlled.

    I have no issue with people spending their money on things that they find entertaining – that is why it is called entertainment – but we call it a scam when a product claims that it will save energy – and in actuality it does not save anything like the amount of energy that it claims.

    A difficult topic – but where is the line between scam – excessive marketing – and marketing?

    As I said – Google “energy scam” – these are without doubt the items that fail any reasonable test!

  18. I did the high-level reset per Nest’s support person, to see if some of my problems could be solved. Nope. Among other things, the Energy panel says its been partly cloudy and raining for the past three days – not even this is correct. Of course, the implication that the Nest is clever enough to use this information is false. The next step would be the low-level reset, which would restore the unit to its as-received state. I’m going to return it instead. It is properly labeled an 0.8 version – not all the functionality is present in the code, and there are unfinished aspects to the code that is.
    Nest showed great attention to detail in its look and feel, in its marketing materials, in its website (which is labeled beta), the apps – but just beneath the surface of the unit itself, it’s a mess. A very bad way to start, it seems to me.

  19. I can’t set the away temperature to 58F or 60F. It always switches it to a lower/higher value. Anyone else seeing that in the web interface currently?

  20. My Nest thermostat worked for 4 days. Then problems. It ended up blowing out the control board in my furnace. Then the replacement. I ended up getting replacing it with the old Honeywell that has worked so well for so long. I got my money back, but they’re completely ignoring me after they refunded the purchase price. I’m still pretty mad about this.

    Some, at least, of their support people don’t know anything about electronics. Because I was concerned about it being powered from the furnace’s 24V line, I asked them how much power the Nest thermostat dissipates, I was told “24V.” I tried to clarify and asked him again, how much current does it draw? He had no clue. I asked what the spec sheet said for max current draw and was told that they don’t have a spec sheet.

  21. I was thinking about a Nest Thermostat but have changed my mind! I was plesantly surprised when I installed a Honeywell Vision Pro and it was able to anticipate the time to turn the boiler on for my Minnesota frosty winter wake-ups. Boilers are notoriously difficult for working with prediction algorithms, the old Chronotherm III was abysmal. If I do replace the Vision Pro, it will be with the new Honeywell Presige with the wireless outdoor temp and remote control! Thanks for all the helpful feedback!

  22. I have had the nest for about 3 weeks now. I’ve been happy with it but I will admit I’m not nearly as obsessive about exact temps etc as some of you guys (not to imply that is a bad thing). I travel a great deal and so for me being able to access the Nest remotely via my phone was the big selling point. I found other thermostats that allowed this but they required me to leave a PC on in my home while out of town. The only issue I’ve seen happened this AM. I got up and the thermostat had reset itself like it lost power I assumed that if it lost power it would just come back up ready to go where it left off. I had to perform the full setup like it was brand new. The critical issue is that I did not lose power last night. None of my clocks were reset so not sure what happened with the Nest. I’ll have to just keep watching to see if this happens again. Anyone else have this happen?

  23. I read about the Nest in the Wall Street Journal back in November or earlier. It sounded great for my shore house, and just what I wanted to control the temperature via the internet. Tried to buy a Nest at Christmas but they were “sold out”. Put my name on the waiting list in January, but never heard from Nest, not even an email confirmation that I am on the list. Finally called tonight, and it sounded like I was talking to a scam artist. No explanation as to why I have not heard anything, other than they are very popular and have limited supply. Who can’t build a mehanical device nowadays – outsource to China or India and they would have piles of these things.

    I am taking a pass on the Nest and will search for other internet controllable thermostats. Hey, at least it looks nice.

    Good luck to all you Nest owners, and thanks for this blog.

  24. Hi David

    Have you had any luck with your 2 degree temp discrepancy? I too have the same issue and nest just gives me the run around. I have insulated it the wall behind the nest, made sure it is out of direct sunlight, ran a c wire. Still constantly higher than my older thermostat and 4 other thermometers. Nest support told me they are aware of the problem and that I should just live with it.

  25. I had same problem with the nest, registering i warmer temp than what it really was, by 5 degrees.. after leaving it plugged in for 1 day.. the battery is now fully charged and the temp has moved to dead on, compared to my 3 other therm’s. GREAT PRODUCT, but they should tell ppl it can take longer than 10minutes to neutralize the readout.. 1whole day in my case..

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