A faint hum from a doorbell transformer can be normal. A new or loud buzz needs a check, especially after installing a smart doorbell. Start by finding where the noise comes from: the transformer or the indoor chime. If you notice a burning smell, smoke, or scorching, stop using the doorbell and get electrical help.
Start with these checks
- Where's the noise? The chime is the box that rings inside your home. The transformer supplies its power and may be in a basement, garage, or closet.
- Did you just install a video doorbell? Check that model's power requirements and compatible chime list. An existing transformer isn't automatically suitable.
- Is the button stuck? Look from outside. A button that stays pressed can keep the chime energized.
- Any burning smell or visible damage? Stop here. Turn off the circuit only if you can do so safely, and call an electrician. For smoke or fire, leave and call emergency services.
If it started after a smart doorbell installation
Look up the instructions for your exact doorbell model. You'll need to check the transformer rating, chime compatibility, and any required power kit. Those requirements vary, even within one brand.
A higher voltage rating alone doesn't tell you whether a transformer is compatible. Ask the installer to compare both the voltage and power rating with the doorbell's instructions. Don't buy a replacement based on the buzzing sound alone.
What to tell the electrician
A short description helps narrow the problem:
- Whether the noise comes from the transformer or the chime.
- When it started and whether anything was installed or changed.
- The doorbell model and whether it still rings or loses power.
- Any smell, discoloration, or tripped breaker.
Leave covers, wiring, and transformer replacement to the electrician. The transformer connects to household voltage. You don't need to open anything or touch it to check its temperature.