If your furnace seems like it is constantly running, it may not actually be running nonstop. In many cases, it is turning off and on every couple of minutes instead of cycling normally a few times an hour. That issue is called short cycling, and it is something you will want to address.
During cold Alberta weather, your furnace will naturally run more often. But it should not be running continuously or short cycling. When it does, it can increase wear and tear, reduce efficiency, and shorten the life of your heating system.
Common Reasons a Furnace Keeps Running
Thermostat Problems
Start by checking your thermostat. Frayed or loose wiring can affect communication between the thermostat and your furnace, causing odd behaviour.
You should also make sure the thermostat is set properly. Try lowering the setting a few degrees below the current room temperature. If the furnace stops after finishing its cycle, it may have simply been working hard to reach a high setting. During a major cold snap, that can happen. But if it keeps happening even in milder conditions, your home may be losing heat too quickly or your furnace may need professional attention.
Dirty Air Filters
Dirty filters are one of the most common causes of furnace short cycling. When airflow is restricted, the furnace can overheat. A safety feature then shuts the system down before your home reaches the desired temperature. Once it cools off, it starts again and repeats the cycle.
Changing your furnace filter regularly helps maintain airflow and reduce strain on the system. In many homes, every three months is a good starting point, though homes with pets or extra dust may need more frequent changes.
Damaged or Leaking Ductwork
Leaking, damaged, or undersized ducts can also restrict airflow and contribute to overheating. If warm air is not moving through the system properly, your furnace may keep cycling on and off without heating the home effectively.
Incorrect Fan Setting
Check your thermostat fan setting and make sure it is set to AUTO, not ON. When the fan is set to ON, the blower can run all the time, which makes it seem like the furnace itself is constantly running.
Fan Limit Switch Issues
A faulty fan limit switch can also cause problems. This switch helps control the furnace blower. If it is stuck in manual override or not working properly, the blower may continue running when it should not.
An Aging Furnace
Older furnaces often become less efficient and more prone to problems over time. If your system is aging and having repeated issues, it may be a sign that repairs or replacement should be considered.
Why You Should Not Ignore It
A furnace that runs constantly or short cycles is more than just annoying. It can drive up your energy bills, increase wear on key parts, and leave your home less comfortable. Catching the cause early can help prevent larger repairs later.
If your furnace is acting up, it is a good idea to have it inspected by a professional. The Gentlemen Pros can help with heating concerns, maintenance, and repair when your system is not performing the way it should.