The on-and-off cycling of your furnace depends on many factors, including proper system sizing, thermostat settings and weather conditions. Cycles that are too close together may indicate an oversized system.
Both infrequent and frequent furnace cycling can result from problems with various parts of your heating system. Inadequate heating and long periods between cycles may result from low temperature settings, meaning that an adjustment is needed to keep a home comfortable. Frequent cycling may result from high temperature settings or problems with a thermostat. Air restrictions caused by dirty parts or filters can also contribute to short cycling. Structural issues like air leaks and duct leaks can also lead to increased furnace activity.