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Does the Nest Thermostat Work if Power Goes Out? [Answered]

Does the Nest Thermostat Work if Power Goes Out? [Answered]

When you turn your entire house into a smart home, you will most likely have a few systems working together. One of the most popular things to change into a smart device is the thermostats throughout the home; with Nest thermostats being popular, the question of power interruptions is natural.

Nest thermostats will continue to work as normal for at least a couple of hours if the power has gone out because every thermostat has an internal battery that will keep them powered. The Nest thermostats have these batteries included ensuring that the system can stay online if the power goes down for a while.

The included batteries of a Nest thermostat will be able to work for about 2 hours without power unless in sleep mode – usually a bit more. However, if the power outage is longer than two hours, they will eventually stop working and will require power to work again.

Many aspects of the Nest thermostats need to be explored, with many questioning the purpose of having a thermostat that is always on. We have gone through some of the most common questions and found why Nest has added some seemingly random features.

How Important Is It for The Nest Thermostat to Have Power?

no electricity

Unless you have a separate power system that is powering the boiler, furnace, or air conditioning systems, having the power to your thermostats is not as important. The power that the Nest has is only to keep the systems themselves on and not to power the rest of the thermal control system.

Instead, the reason that Nest has built in the battery is to ensure that the thermostats do not lose their settings. Most Nest thermostats go into a sleep state if your power is off for an extended period, helping you gain quicker control when the power does return.

We have seen several people who refer to the internal batteries as nothing more than an added gimmick; however, the batteries ensure you do not lose your settings. Otherwise, you would have to reconnect every Nest thermostat throughout the house every time you lose power for any reason.

How Long Does the Nest Last Without Power?

If the Nest thermostat is not allowed to go into sleep mode, the battery will last between one to two hours. However, if the automatic surge protection turns the thermostat off, the battery will last for several days, keeping the internal components charged with a low voltage level.

Nest thermostats do have long-term memory, which means that even if the battery is completely dead, they will remember your settings. However, the immediate operations and the memory of what happened before the power went out will be lost without the battery.

If your battery is starting to fail quicker and quicker, it may mean that it has been damaged, which will require that you replace the battery. While the Nest can work without the battery, it will require you to start up from scratch each time your power even trips for no reason.

However, you should not expect to have to change the battery too often, as it should work without problems for several years under regular usage.

What Happens If the Nest Thermostat Loses Power?

When the power to your home goes off, the Nest will stay active and fully functional for a few minutes, trying to re-establish its Wi-Fi connection. Once it has determined that there is no power to the home, it will enter a full sleep mode, sending a low-level voltage to each component.

If the Nest has been allowed to enter this state, the internal battery can last for several hours, waking up automatically once the power is restored. If you lose power for several days, the battery will run out, and some of your settings will be completely lost, requiring you to set them back up again.

Further, allowing the battery to be completely drained will damage it; the battery will become completely useless with repeated damage. Requiring that you either replace the battery yourself or send the Nest to a licensed dealer to have it completely replaced.

How Do I Turn on The Nest Thermostat After a Power Outage?

nest thermostat working without power

The first and easiest thing to try will always be to restart the entire Nest thermostat, turning it off and then on again as normal. To do this, go to settings, reset, restart, and then press the ok button using the ring on the Nest itself.

It is best not to do this through an application as there may be some fault with the Wi-Fi connection, making errors a likely thing to happen. We always recommend giving the router a good restart, helping it shut down properly, clear all the caches, and reconnect to everything.

However, with everything being built to be automatic, if you have set everything up properly, all of this should happen automatically. With the Nest starting up on its own while the Wi-Fi router starts up and allows everything seeking a connection to reconnect to the internet.

What Happens to A Nest Thermostat When Wi-Fi Goes Out?

If the power outage has caused your router to fail or your Wi-Fi is not allowing connections, then the Nest thermostat will work as a traditional thermostat. Allowing you to change the temperature and setting directly at the thermostat using the ring and buttons.

It is important to remember this when your internet starts to act strangely, and you realize that some of the smart devices are becoming a pain to handle. However, Google has already thought about this and has ensured that your Nest will still be perfectly usable if your Wi-Fi is acting up.

The Nest can work as a normal thermostat that is usually the first thing that people purchase when they start making their homes smarter. You can have the Nest thermostat installed long before you have even built the environment for a smart home, using it to control the temperature easily.

How Do You Check a Nest Battery Level?

On the standard Nest itself, navigate to the menu, then Settings, and click on the battery icon; this will show you the current levels of your battery. It may say that it is very low, so you will have to replace the batteries, which is a quick process when you have the standard Nest.

However, if you have a Nest E or a Nest Learning Thermostat, you will have to navigate to the Quick View Menu, Settings, Technical Info, and Power. If the rating is 3.8V, then the Nest has enough power; however, if it has lower, then it means that the battery is starting to run low.

Replacing the batteries of a Nest E or Nest Learning Thermostat requires a few tools and a specific battery type they use Lithium-Ion batteries. We have focused on these simply because you are much more likely to have a Nest E or Nest Learning Thermostat in 2021 than you are to have a normal Nest.


Your Google Nest does have a set of batteries that needs to be changed or charged whenever you have gone for a long time without power. In some cases, you can put in brand new AAA batteries; however, it is much more likely that you need to wait for the battery to be charged through wiring.

Whatever you do, please don’t expect the small batteries inside the Nest to somehow provide power to your entire climate control system!

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