Short cycling is an annoying problem that prevents your furnace from finishing a normal heating cycle. This is most often because the thermostat is set too low or the furnace itself is too powerful for your home. The furnace will generate heat quickly, which reaches the thermostat faster than the rest of the house. As a result, the cycle ends before the entire home gets sufficient heat. This can also happen when the furnace is repeatedly overheating, as the safety components stop the heating cycle before the desired temperature is reached.