The answer to 'thermostat short cycling' is that short cycling, where the HVAC system turns on and off rapidly, is usually caused by issues with the thermostat or other components. Common causes include a malfunctioning thermostat, a problem with the HVAC system itself, or an issue with the home's insulation or airflow.
Symptoms of short cycling include the system turning on and off frequently, the home not reaching the desired temperature, and higher energy bills. Solutions may involve replacing the thermostat, cleaning or repairing the HVAC system, or addressing insulation and airflow issues. While some basic troubleshooting can be done by homeowners, it's generally best to call a professional HVAC technician to diagnose and fix the problem, especially if the issue is with the HVAC system itself.