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Nest 3rd Generation Thermostat Destroyed my Nest (as in Home)

gdking
Community Member

If you live in a cold climate and rely on Nest Learning Thermostats you are at risk of a catastrophic heating system failure.   https://www.nytimes.com/2016/01/14/fashion/nest-thermostat-glitch-battery-dies-software-freeze.html

In my case the batteries in my two Nest Learning Thermostats died while I was away from home and failed to turn on my heating system resulting in most of the water pipes in my home bursting and flooding the house. My 2 Nest Learning Thermostats are wired to W1 HEAT and Rh POWER but as it turns out POWER is not really powering the device without a third C wire. If you own one of these dangerous thermostats, please read the following article. It's too late for me as my home has sustained major damage, my family has no home to live in and we are facing a long restoration to our vintage 1886 Carriage House. 
https://www.smarthomeperfected.com/nest-thermostat-battery/

Google Nest should sell this product in cold climate states with a warning label about the possibility of it failing to do its primary function, turning on a heating system in the cold. Once the batteries die the device cannot and will not send a signal to your heating system. Since posting my experience on LinkedIn I have learned that many others have encountered this problem while at home so it's obvious that the company can do more to inform consumers so that others avoid the pain I am experiencing. 

7 REPLIES 7

johnCNA
Bronze
Bronze

That's awful to hear of what happened in your situation.

The cause of your problem is not limited to Nest thermostats, though.  That will apply to all smart thermostats.  PC Magazine published reviews of the top 10 smart thermostats for 2022 and 8 of the 10 require a C-wire for providing power and backup battery charging.  Even the two battery-only models will fail when the batteries go dead.  That's a pretty serious limitation of all smart thermostats that are not powered by the furnace.

https://www.pcmag.com/picks/the-best-smart-thermostats

 

gdking
Community Member

Thank you for sharing your expertise and the PC Magazine article. In a cold climate like Massachusetts NEST should require that all installations require use of the C wire. I was unaware that that the wire labeled POWER in the app cannot power the device without the complementary C wire. I had no idea I was putting my home and family at risk because of the potential of a battery failure. I have learned a very expensive lesson and want to make sure that others do not find themselves in my situation, homeless due to no heat and running water, push back from my insurance company on my claim, living in a hotel and uncertain when I will be able to return to my home. 

Your post made me realize the common failure point of all programmable thermostats, especially those that run on batteries only.  We've had near zero temps in Chicago lately and just the other day temps dipped to -15F actual (not wind chill) overnight.  Wouldn't take too long for a dead battery to cause a catastrophic house freeze.

Prior to buying the Nest Learning model, I had researched several others; even to the point of downloading the installation and setup instructions.  None of them provided any cautionary warnings of potential catastrophic results if the batteries were to go dead during a cold spell.

You're right that these companies are making it sound almost trivial to DIY install these things and are not giving enough attention to the need for constant power supply connections.

I mean to be fair, the combination of circumstances that resulted in this issue are extremely rare.  One has to have an older furnace control board that runs enough current through the switch circuits to charge the nest battery during normal operation and then see a situation where the system is not used for long enough that the battery in the Nest goes dead and then requires an emergency activation all without anybody being there to notice a problem.   Generally speaking if its cold enough to require emergency activation, it will do so long before the battery goes dead and then will recharge the battery when it runs to maintain the minimum temp.  It's difficult to account for every potential issue when writing manuals or install instructions as if you did they would usually become so long and complex as to be unintelligible anyway.

Thanks for responding to my posting. I do have an older furnace and we were away for a month but monitoring the home via the Nest indoor and outdoor cameras and thermostats. I never received a low battery alert and both went offline (likely to conserve energy) before failing. Once I was back in my home I did take both thermostats off the backplate and used a micro USB cable to charge the thermostats for 24 hours. Once I place them back on the backplate I immediately get "Your Thermostat needs to shut down in order to recharge its battery." followed by "The thermostat is shutting down." The device then becomes non-responsive. Tried this several times before concluding the batteries are no longer capable of accepting a charge. Apparently, the battery is embedded and cannot be replaced except with an aftermarket battery. The Google Home app is deceiving with its wire labeling. POWER from the Rh is apparently not really power that you can rely on to protect your home.      

Ryan_G
Community Specialist
Community Specialist

Hey folks,

 

Thanks for visiting the Google Nest Community. 

 

Since this thread hasn't had activity in a while, we're going to close it to keep content fresh.

If you have additional questions, feel free to submit another post and provide as many details as possible so that others can lend a hand. 

 

Hope this helps!

 

Kind regards,

Ryan


 


 

It's a bit late for it now but this is how you solve the issue when you don't have a C wire.  

https://store.google.com/product/nest_power_connector?hl=en-US