How to charge Nest Thermostat

How to charge Nest thermostat

We sometimes hear friends complaining about the low battery issues on the Nest thermostat. So we thought we would tell them about how to charge a Nest thermostat.

A couple of you may think, when your thermostat isn’t working, you should turn it off then turn it on, which is restarting may help the issue. But manual restarting doesn’t always solve the problem. So the next time your Nest thermostat switches off and won’t turn on, try charging it. And for God’s sake, don’t restart it while loading.

How to Charge Nest Thermostat

You can do it by following these steps. It is essential to mention that when running normally, your thermostat will not need charging. If it is working correctly, it should charge itself without any intervention from you, from the power supplied by the HVAC system. However, the battery may get low due to specific reasons and cause you to charge them. You will also need to check a couple of things before you change things. All the steps include:

  1. Checking the power supply. It is pretty obvious that you will need to check the power switch before you work with electronic devices and thermostats. But even the commonest of issues skip our head, and whom do we blame? You can think that your thermostat broke when all you needed to do was to check the power switch and find that someone accidentally turned it off. It is possible due to remodeling, or maybe when one of the house members was cleaning, it got turned off. It can be your child too. If that is the case, simply turning on the main power switch will solve all issues related to charging. And you will see that it wasn’t much of a problem after all!
  2. If that is not the case and the power switch is just how it should be, proceed to his step. Beside your HVAC system arrangement, there should be a light switch. This controls the power to your system. Make sure that it is on. When this is powered on, power is supplied to your HVAC system. With this power, the Nest charges itself. If somehow, this was off for one or two days, your thermostat will take a long time to recharge. Think a couple of hours

 If you are uncertain that turning the power on to the HVAC system actually worked, you can do a manual check. All you have to do is take off the front cover, confirm that the LED lights on the circuit board are lit, and that’s it. If this is all right, there is power supplied.

  1. Again if this is not the issue, time to move on to check something else! Now, you have the check whether the circuit breaker is on.
  2.  If doing any/all three of these does not work, you have to take Nest off the wall and recharge it. This will not only help you charge the thermostat but also detect underlying problems on the wiring, the furnace, the HVAC system, and the thermostat itself.
  3. You can use a phone charger or a standard micro USB cable to charge the thermostat. You could also get an exclusive charging wire and charger for your Nest thermostat.
  4. On the back of the thermostat, there is a charging port. Simply plug in the micro USB cable or whatever else is allowed/owned to this port.
  5. After the Nest is manually charged, you can try checking the switch off the HVAC system again. That should be on. But after mounting the thermostat back, if it shows low-power or it doesn’t charge itself automatically, you will need a universal wire transformer. This will provide power to your Nest due to the lack of it from the HVAC.
  6. Lastly, when everything else is tried and tested, but nothing seems to do the job, you have two options left at hand: change the batteries or call a professional. But it is infrequent for you to need to change the batteries so any one of the above tasks should help.

Additional Issues

These might also be the reasons for your Nest, not charging:

  1. Your HVAC power is off, as mentioned before.
  2. The small fuse inside your HVAC unit is broken or blown up. In that case, you will need to buy replacements of the 3 amp fuse.
  3. You need a standard wire transformer.
  4. Your HVAC system is broken and needs redoing. When failing, these systems turn the power off, and hence the thermostats show a low battery due to not being able to charge themselves. Try working with your flame sensors, furnace filters, etc.
  5. Your Nest battery is dead (rare but may happen).


You should now be able to charge the thermostat on your own. But make sure you follow each step consecutively. When one doesn’t work, then only move to the next segment. Don’t think of changing batteries as the first!