Furnace short cycling happens when your heating system turns on and off far more often than it should. It puts extra stress on components, raises energy bills, and leaves your home unevenly heated. Sherwood Mechanical explains the most common causes, including clogged filters, dirty flame sensors, blocked PVC vents, poor thermostat placement, and furnaces that are too large for the home. Find out which easy fixes to try first and when short cycling means your furnace needs a professional diagnosis.