Why Does My Thermostat Click When It Comes On?

January 10, 2020

The thermostat controls all the functions of your furnace, central air conditioning or heat pump. It detects the interior temperature and triggers the start and end of a heating or cooling cycle. When the thermostat signals to the heating or cooling system to turn on or off, you may hear a click. Here are some reasons why this click may happen.

1. Relay of Power

The click you hear from your thermostat is probably the electrical relay triggering the power to the furnace, air conditioner or heat pump. It is a normal sound. The sound should be soft and barely noticeable. Everyday household noise, such as people talking, food cooking or computer fans running might obscure the sound, so you might only hear it when the house is otherwise silent. The thermostat typically clicks once when it triggers the start of a heating or cooling cycle and once when it signals the end of a cycle.

2. Mechanical Action

Within the thermostat, there is a bi-metallic strip. The snapping of this strip is supported by the relay switch. The snap might sound like a clicking sound. Older thermostats may be poorly insulated, which would make the click seem louder.

3. Loose Mounting

If you have recently taken the cover off of the thermostat to paint or rearrange some furniture, the click of the thermostat might get louder. This could be a result of loose screws holding the thermostat’s housing to the wall. The thermostat’s cover might be slightly out of alignment if it was removed to update the programmed heating and cooling schedule. You can tighten the screws or readjust the housing. At C & C Heating & Air Conditioning, our NATE-certified technicians are available to check your thermostat if the clicks get louder or the thermostat behaves in an irregular way.

Contact Us Today

If your thermostat, heating or cooling system makes unusual sounds outside of a heating or cooling cycle, contact us at C & C Heating & Air Conditioning in Roseville, MI. We’re committed to resolving all of your HVAC installation, repair, and maintenance needs.

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