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What Transformer Do I Need for Nest Hello?

Last Updated Jan 5, 2022
wiring for doorbell transformer
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Nest Hello is a top choice in the Smart Doorbell world for its consistent performance along with easy install. You don’t need an electrician to install a new Nest Hello outside of your home, it’s a pretty simple process that most homeowners can do on their own. However, having the right transformer is a must.

With the Nest Hello, a 16V transformer is the best choice for the job. While a 24V transformer will technically work but it is not the recommended choice because it is stronger than it needs to be, and bigger is not better here.  A 16V transformer is the perfect fit.

Ready to find the right transformer so you can install your Nest Hello? Then you’ve come to the right place! Stay tuned and keep reading to answer more questions to help you navigate your way to the right transformer for your Nest Hello.

Can I Use a 24V Transformer on a 16V Doorbell?

This question can be a little difficult to answer because technically, the larger transformer will work in theory.

The problem is it is not safe long-term to do so. These devices list what size transformer they require to work properly. Typically speaking, they are able to go 20% above or below this number without much trouble. When calculating, you can see that 20% is roughly equal to 5V. Therefore, a 24V does not work.

Looking further into this topic, the previously mentioned overvoltage that would occur in this scenario would probably lead to damage. The most likely damage would occur to the doorbell itself, but you also run the risk of causing a fire, as well.

The main caveat here is if the wiring in your home is extremely long or you have more than one doorbell hooked up for some reason. In these scenarios, a 24V would work because of the reduced power going over long distances (long distances here meaning 75-80 or more).

What Power Supply Do I Need for Nest Hello?

There are a couple of options for power supplies on the Nest Hello. The best option depends on your situation.

A hardwired, 16V transformer would work well enough in the majority of situations. The main exception is in regard to the distance of wiring mentioned before along with possibility of a second doorbell. These two cases would require 24V.  12V transformers are fairly common but do not provide enough power for the doorbell to work.

Nest also has versions of the doorbell that are battery powered. These devices can run anywhere from 1-6 months depending on usage per charge. A simple AC adapter is all that is required to charge the device and can be plugged into any standard outlet. From almost empty, the battery in the Nest Hello takes roughly 5 hours to charge.

Yet another option is the indoor power supply. This allows for the Hello to be plugged into a standard AC outlet all the time. A small hole just needs to be created to allow for the cord to be plugged in. The indoor power supply takes all guesswork out since no hardwiring is required. Furthermore, you do not need to worry about having to recharge the device since it has consistent power.

Which Doorbell Transformer Do I Need?

The Nest Hello doorbell requires a 16V transformer. 16V provides enough power for the device to work properly and also not be overloaded. As previously mentioned, if the wiring run is long, a 24V transformer could be used to ensure enough power gets to the doorbell. If there is any question as to compatibility, an electrician should be contacted to make sure no harm is done in installation.

Another possible reason that would make a 24V transformer necessary is the usage of two doorbells on the same line. The second doorbell would take too much power from the 16V to consistently work. But again, in normal situations, a 16V transformer is more than adequate for the job.

Will Nest Hello Work With 12V?

Nest Hello requires a minimum of 16V of power to work. A new transformer would need to be purchased and installed to make the standard Hello work. 12V is simply not enough power to work properly.

The one and only exception is with the 2021 Nest Hello that has a battery preinstalled. This version of the doorbell does not require any hard wiring and therefore needs no transformer at all. The standard AC power supply that is available from Google is all that is needed which takes all guesswork out of the equation.

Final Thoughts

The Google Nest Hello doorbell has become one of the industry leaders in smart doorbells. The combination of features, price, and ease of use means its lead in the space probably will not go anywhere anytime soon. Furthermore, with the various options in installation, anyone is really able to install the device even without a strong electrical background.

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