The answer to 'thermostat making loud noise' is that a noisy thermostat is usually caused by a problem with the internal components or wiring. Common symptoms include a clicking, buzzing, or humming sound coming from the thermostat. This can be caused by issues like a faulty control board, worn-out parts, or loose connections.
In most cases, a noisy thermostat will require professional repair or replacement. Homeowners should avoid trying to fix it themselves, as improper handling could damage the thermostat or the HVAC system. It's best to call a licensed HVAC technician to diagnose and repair the issue properly.