Tuckers Air Conditioning, Heating & Plumbing Blog

Furnace Short Cycling, and Why It’s a Problem

Is your furnace cycling on and off every few minutes? That’s called short cycling, and it’s an indication of a serious problem with your system. If the cause of the short cycling isn’t found and fixed as soon as possible, you may have to replace your furnace much sooner than you would otherwise have to. Read on to find out why short cycling happens, and what to do about it.

Short Cycling

Short cycling is caused by heat becoming trapped in the central chamber of the furnace, or plenum. As the furnace continues to generate heat, the internal temperature of the system will rise until it activates the limit switch. The limit switch shuts the furnace down to prevent it from becoming damaged by overheating. Once the furnace has had a short time to cool off, it will activate again and overheat again. This cycle of starting, overheating, and shutting down places the furnace under a lot of stress, as well as causing a sharp decline in efficiency.


A furnace is not designed to operate in the way that short cycling forces it to. The system wears down many times faster than it normally does as long as it’s short cycling, which will shorten its lifespan by a number of years if the problem isn’t fixed. This is why you can’t afford to ignore short cycling if your furnace is doing it. Shut your furnace down and call for repairs as soon as you notice it rapidly turning on and off. If the short cycling is dealt with quickly enough, there probably won’t be any lasting damage.

Tuckers Air Conditioning, Heating & Plumbing provides a full range of furnace repair services throughout Bethesda, MD. If you need furnace repair services of any kind, call today to schedule an appointment with one of our experts.