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Furnace short-cycling is when your furnace frequently turns on and off without reaching the set temperature on the thermostat. When your furnace starts short-cycling, you may notice that your home isn’t as warm as it should be. 

When your furnace works correctly, it will turn on when the temperature drops below the set number on your thermostat. Then, it will continue warming your home until it reaches the desired setting before turning off. However, when your unit begins short-cycling, it can cause a wide range of efficiency issues throughout your home. 

Your reliable team at Reggie Broussard’s Air Conditioning & Heating provides furnace tune-ups in Centerville, LA, which can prevent these types of issues from developing. Depending on certain factors, such as your furnace’s condition and the outdoor temperature, a cycling furnace should only happen three to eight times per hour. However, if it runs too often or your furnace turns off after only a few minutes, it may have a problem. 

What Causes Furnace Short-Cycling?

Bad Flame Sensor

A bad flame sensor is a common cause of furnace short-cycling. When your furnace burns fuel, the system produces small amounts of moisture during heating. Over time, this moisture can cause metals to corrode and rust, which causes frequent short cycling. 

A dirty or damaged flame sensor will also turn off the gas valve and the furnace. This step can prevent natural gas accumulation that can result in a fire. 

Flame sensors need regular cleaning and inspection to prevent wear and damage. In addition, we recommend contacting an HVAC professional to inspect your furnace because dangerous flammable gas and electricity are involved.


When your furnace has faulty temperature-monitoring components, it can overheat, causing it to shut down. An overheating furnace is one of the most frequent causes of a short-cycling issue. 

Most modern furnaces include a heat exchanger, which can cause overheating when it breaks down. In addition, a cracked heat exchanger can leak warm air into other components of your furnace. 

Dirty Air Filter

A seemingly minor issue like a dirty air filter can cause problems, including a short-cycling furnace. A dirty furnace filter can block airflow, which eventually causes a backup that ruins its heating efficiency. In this situation, warm air gets trapped in the unit instead of spreading out to areas of your home. As a result, your furnace’s internal temperature will rise, causing it to overheat and stop working. 

We recommend replacing your furnace’s air filters according to your heating system’s manual to avoid this situation. In addition, keeping up with essential furnace maintenance can be an excellent way to prevent short-cycling.

Thermostat Issue

If you’re experiencing a furnace short-cycling issue, one of the first things you can do is check your thermostat. Homeowners may forget to switch their thermostats over to heating mode. Also, remember to change your batteries every six months. 

Additionally, if you have a faulty thermostat, it can cause short cycling in your furnace. A furnace repair technician can diagnose this issue and repair it. 

Clogged Exhaust Flue

Your furnace has an exhaust flue that removes dirty air from your home. Unfortunately, birds and other small animals can enter your area, often building their nest there. Additionally, leaves and other debris can accumulate in your system, resulting in a clog. 

When you have a clogged exhaust flue, your furnace will shut down to protect your home from potential issues with carbon monoxide. This scenario is another possible cause of furnace short-cycling, which a professional HVAC technician can diagnose and repair swiftly.

Contact Reggie Broussard’s Air Conditioning & Heating Today!

If you’re having trouble with your short-cycling furnace, call our team of HVAC professionals at Reggie Broussard’s Air Conditioning & Heating today! We provide furnace repairs in Morgan City, LA, and the surrounding areas. 

Our certified technicians can diagnose and repair any issues with your heating system. In addition, we provide 24/7 emergency service to keep your home comfortable. Contact us today!