How do I measure the voltage of my doorbell transformer?

We recommend that you check the voltage level on your doorbell transformer before you install the Power Kit for your Arlo Essential Video Doorbell Wired, or before you hardwire your Arlo Essential Video Doorbell Wire-Free. If your doorbell transformer does not meet the required voltage, you must upgrade your transformer before you use your Arlo doorbell.

Required voltage:

You can check the voltage level of your doorbell transformer by one of three methods:

  • Use a multimeter to test the voltage.
    Using a multimeter gives you the most accurate estimate of your doorbell transformer’s voltage, and it can be done without finding the doorbell transformer. Read the next section for detailed instructions about using a multimeter to check voltage.
  • Check if the voltage is printed on your existing doorbell transformer.
    The estimated voltage is commonly printed on doorbell transformers. This is typically accurate, but it is not as precise as using a multimeter.
  • Try using the Arlo app to install your Arlo doorbell to see if it works with your doorbell transformer.

Use a multimeter to check the voltage level

A multimeter is an electronic tool that measures the precise voltage level of an object.

To use a multimeter to check the voltage of your doorbell transformer:

  1. Disconnect your existing doorbell.
    Note: Make sure that the wires from the doorbell don’t fall inside the wall.
  2. Set the knob on your multimeter to AC (the V with a wavy line on top or next to it).
  3. Connect the two probes from the multimeter to the wires from your doorbell.
  4. Read the voltage level on your multimeter’s display.
    If the voltage level is between meets the voltage requirement, you can use the doorbell with your current doorbell transformer.

Check the voltage level by finding your doorbell transformer

A doorbell transformer is a device that sends the right amount of electricity to power an electric doorbell. Your doorbell transformer can be anywhere in your house, but it’s commonly found in a few places, as listed below.

If you plan to use a multimeter to check the voltage, you do not need to find your doorbell transformer. You can check your doorbell transformer’s voltage from the wires that are connected to your existing doorbell.

Look for your doorbell transformer in these common places:

  • In a front closet
  • In the wall next to your existing doorbell
  • Near your house’s circuit breaker
  • In the basement or attic
  • In the garage
  • Near your house’s furnace
  • In the crawl space under your house

Note: We recommended that you turn off power at the breaker before accessing your transformer.  When in doubt, consult a qualified electrician.

Once you locate the transformer, check if there are markings to indicate the voltage and power rating. The Arlo Essential Video Doorbell Wired requires 16-24V AC for reliable operation. The Arlo Essential Video Doorbell Wire-Free requires 8-24V AC for reliable operation.

Alternatively, if your transformer has a model number shown, you can search the manufacturer website for technical specifications.