Check your doorbell and existing chime specifications for the required AC voltage and power rating, then choose a low-voltage doorbell transformer that matches those requirements, such as a 16 VAC transformer with sufficient VA output. Confirm that the transformer’s wiring terminals and mounting style fit the existing installation, and follow the doorbell and chime manufacturers’ wiring instructions.

Low-voltage doorbell transformers connect to a 115-volt AC line input and provide a low-voltage AC output, such as 16 volts at 30 VA or 16.5 volts at 40 VA, for compatible doorbells and chimes. Turn off power before installation, confirm the transformer’s voltage and VA rating match the doorbell system, and use the appropriate mounting method, terminals, and existing low-voltage wiring, with line-voltage connections completed by a qualified electrician.

Choose a plug-in low-voltage doorbell transformer when you have a nearby receptacle and want a straightforward installation without replacing an existing in-wall transformer. Choose a hardwired transformer when the system has an existing transformer location and wiring, particularly for a drop-in replacement that powers a compatible video doorbell and indoor chime.

Yes, a low-voltage doorbell transformer can support a smart doorbell and an existing indoor chime at the same time when its voltage and power output meet the requirements of both devices. Confirm the doorbell manufacturer’s specifications, transformer capacity, and existing wiring before installation, since some smart doorbells may require a compatible chime connector or a different wiring arrangement.