Sudden Nest Thermostat Reading +6 Degrees Higher Than Actual Temperature After 4 Years of Use

[JackHammer7]

Hello Nest Community,

I'm reaching out because I’m having a frustrating issue with my 3rd Generation Nest Thermostat, which has been running smoothly since I installed it 4 years ago. However, in the past month, I’ve noticed that it consistently shows the temperature as 6 degrees Fahrenheit higher than it actually is. I have a separate Nest temperature sensor in another room, and its readings remain correct. I have confirmed with a separate thermometer.

I've already tried resetting the thermostat, and this initially seemed to correct the error, but the temperature discrepancy returned within a day. I’ve also read recommendations to check for drafts behind the thermostat and to add insulation if needed. However, there haven't been any changes to the thermostat’s surroundings over the years, so I’m skeptical that drafts could be causing this sudden shift in temperature readings.

If anyone could provide guidance or advice, it would be greatly appreciated. Also, please let me know if the thermostat may simply need replacement. I had hoped it would last longer than 4 years, so I’m eager to hear any insights you can share.

Thank you for your help!

[Stueyg]

Exactly the same issue here, worked perfectly for years, and couldn’t work out why I was struggling to get the house warm, worked out today the Nest Gen 3 thermostat is inflating indoor temps by c2C thus kicking the boiler off before the house is sufficiently warm. I’ve had to up the ambient temperature in the app as a workaround. Spoken to Google who went through rudimentary troubleshooting and am now waiting on a response. 

[bertjan93]

i have just installed a gen3 as well, almost wish i didn't buy one

i noticed the reading gets higher when you control it for a while, almost like the cpu is next to the sensor

i disabled motion activation and enabled wifi airtime fairness on my router so i will test if that helps but i dont have any hope

how hard is it for a billion dollar company to include a calibration or offset feature

[Stueyg]

Update to my post above, surprise, surprise, Google told me (finally) faulty thermostat and as out of warranty, replace. Appalling! 

[JackHammer7]

Wow! That's really unfortunate.  I love that there is new technology in household equipment like thermostats, and they've been great, but when they only have a lifespan of a few years, that's very disappointing.  My grandmother has been rocking the same thermostat in the house for over 50 years!  Although I'm okay with them having a lifespan, I think it should be much longer than a couple of years.