Why Thermostat Is Clicking?

Thermostats are often placed in living rooms and bedrooms and the device’s ability to operate quietly is definitely an important feature. However, not all thermostats are completely silent.

The majority of thermostats will make a clicking sound when they call for heating and cooling. However, constant clicking is not a normal thing – a short-cycling HVAC system, issues with the wiring, a malfunctioning relay switch, and an issue with the capacitor or motor can cause the sound. 

Why Thermostat Is Clicking?

It is absolutely normal for a thermostat to make a clicking noise when a signal is sent to your heating and cooling system. 

Relay switches are devices that open and close circuits. When this happens, the switch makes a clicking sound.

However, this sound might also serve as an indication that there is something wrong with the system. If you can hear the clicking noise not only when the heating and cooling switch on and off, then:

  • The thermostat is experiencing rapid temperature changes
  • The heating and cooling unit is not responding and the thermostat is making the relay switch try over and over again
  • The mounting screws are either too tight or too loose
  • The wire between the thermostat and the HVAC system is damaged
  • The HVAC unit is short-cycling

Read: Temperature Thermostat Problems

Thermostat Keeps Clicking On and Off

The device might be constantly clicking on and off if the HVAC system is short-cycling.

This might be happening because of the actual thermostat. If the device is placed in direct sunlight, close to a vent, or near a drafty window, the thermostat might be registering frequent temperature changes.

Your HVAC unit can also short-cycle, if:

  • The heating and cooling system is not properly sized for your house
  • There is a blocked vent
  • The air filter is dirty
  • The blower motor is broken

Emerson Thermostat Keeps Clicking

  • There is an issue with the wiring
  • The capacitor or the motor is faulty
  • The relay switch had gone bad

Honeywell Thermostat Loud Clicking

A lot of users have reported that Honeywell thermostats make a loud clicking sound when the AC or heating is activated

You might find that annoying if you have the thermostat in the bedroom as the system might turn on and off a few times throughout the night.

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Read: Benefits Of A Programmable Thermostat

Sensi Thermostat Clicking Noise

A lot of Sensi thermostats also make a relatively loud clicking noise when calling for heating or cooling which some users might find to be extremely irritating.

Are There Thermostats That Don’t Click?

The clicking sound is produced by the thermostat’s electrical contacts that are completing a circuit.

In a mechanical device, a bimetal coil makes the sound, while in a digital thermostat the click can be produced by the small circuit boards that register the temperature and complete the electrical signals.

If you want your device to be practically silent, then look for a thermostat with a solid-state relay.

Read: Thermostat Wire Color Code

Do Smart Thermostats Click?

In a nutshell, any electronic thermostat is going to make a clicking sound. However, there are devices (Nest thermostat, for example) that use solid-state switching which is a lot quieter.

The smart thermostats that don’t have mechanical relays shouldn’t be ‘clicking’ when there is a call for heating or cooling. If you ever hear such a sound, it means that there is something wrong with the unit.

How Do I Stop My Thermostat from Clicking?

Check the thermostat for damaged wires

You would have to expose the circuit board and remove the thermostat wires from the terminals. Next, use a voltmeter to test the red and white wire (if there is no signal or it’s lower than 24V, then the wire has to be replaced).

Make sure that the HVAC system is not short-cycling

Relocate the thermostat, if necessary. Ensure that the system is receiving sufficient airflow, that the unit is of the right size for your house, and that the blower motor is not broken.

Ask a technician to deal with the problem

The thermostat might be clicking if the mercury bulb had cracked or one of the relays within the device had failed. The professional will temporarily install a new thermostat and check if that fixes the issue. 

Can Thermostats Make Noise?

Thermostats can make noises on two occasions – during normal operation and when something is wrong.

The majority of thermostats that are working correctly will be making a clicking noise from time to time. So, if you hear a ‘click’ when there is a call for heating or cooling, there is nothing to worry about.

However, a constant clicking noise, hissing, buzzing, and other sounds might mean that one of the device’s components is malfunctioning. 

Read: HVAC Thermostat Problems

Why Does the Thermostat Make Noise?

A constant clicking noise

The thermostat might be clicking, if the relay switch had gone bad, the motor or capacitor had gone bad, the HVAC system is short-cycling, or there is an issue with the wiring.

A hissing sound

Pneumatic thermostats can make a hissing noise when they are telling the heating and cooling system to kick in. However, a constant hiss means that there is an air leak in the tubing connected to the thermostat.

A buzzing noise

The device can start buzzing, if there is a loose connection in the wiring, or if the cycling contacts or the bimetallic strip inside the thermostat are dirty or worn out.

Why Is My Honeywell Thermostat Making Noise?

Some Honeywell thermostats will make a clicking noise when they are calling for heating or cooling

Any other sound coming from the thermostat is not normal, so you would have to try to find the cause of the problem as soon as possible.

Why Is My Thermostat Chirping?

Thermostats should not be chirping. You might want to double-check, if the noise is coming from a nearby device (like a smoke detector, for example).

If you are sure that the sound is coming from the thermostat, then you can try resetting the device

Can a Thermostat Beep?

A lot of thermostats are not capable of making a beeping sound. It might be another device making the noise, like the CO2 alarm or your furnace.

Some thermostats can produce a sound when one of their buttons is pushed in. Simply make sure that the buttons are not stuck.

Does a Thermostat Beep When the Battery Is Low?

Some models do have a low battery indicator and might start making a quiet beeping noise when the batteries are about to die.

To check if your thermostat is supposed to be making such a noise, consult the owner’s manual

Why Is My Emerson Thermostat Beeping?

In some Emerson thermostat models, the device will start making a beeping sound every 5 minutes when the batteries need to be replaced

Why Is My Lennox Thermostat Beeping?

Lennox thermostats do not make a beeping noise. There might be another device somewhere next to the thermostat that is producing the sound. 

Can a Thermostat Cause Short Cycling?

Your thermostat can make a constant clicking noise if the HVAC system is short-cycling. But can the actual thermostat cause the heating and cooling unit to turn on and off more frequently?

Read: No Power To The Home Temperature Thermostat – Troubleshooting Guide

The thermostat’s placement can cause the system to short-cycle

If the device is close to the window, vents, or heat generating appliances, then it won’t be able to correctly read your house’s average temperature. Consequently, the thermostat will tell the heating and cooling system to switch on, when it’s not supposed to be on.

You have an older thermostat model

Older devices are not as intuitive as newer models. Moreover, your thermostat might simply start malfunctioning, if it’s over 10 years old.

Loose wiring

Loose connections are the most common reason for short cycling. If the wires in the thermostat are not properly connected, then the device might start telling the HVAC system to run on and off at irregular intervals.