Fixing a Relationship with a Short-Cycling Furnace

Is your relationship with your furnace very on-again, off-again? 

While all furnaces cycle, if you’re not getting what you need from your furnace—that would be heat and efficiency—it might be time to evaluate whether your furnace has cycling issues that should be addressed. 

Read on to learn about furnace cycling, how it can affect you, and what you can do about it. 

What Is Furnace Cycling?

Simply put, furnace cycling is when the furnace switches on and off. When your furnace is in “auto” mode, it will turn on and off throughout the season to maintain your home’s temperature. 

Basically, it stays on long enough to heat to a specific temperature. Then it remains off until the house temperature falls below a particular temperature. Each of these cycles can take anywhere from several minutes to a half hour, depending on the heating needs of your house. 

What Is Furnace Short Cycling?

Short cycling is when your furnace goes on and off very rapidly. In this case, your furnace will be on for an extremely short period—sometimes seconds and no more than a couple of minutes—before turning off. 

What does it mean if your furnace is short cycling? It means your house doesn’t heat thoroughly or efficiently—a big problem during those chilly winter months. 

How Often Should Your Furnace Cycle in Winter?

Furnace cycling needs are dependant on the weather outside. When temperatures are very low, your furnace will need to remain on, without a break, for longer durations to maintain indoor temperatures. So for Minnesota winters, cycling frequency should typically be no more than 2-3 cycles per hour. 

However, more frequent start-ups don’t necessarily mean that your furnace is short cycling. If your furnace only remains on for several minutes after it starts up, it could just be that the furnace is not the right size for your house, or you need some more insulation. 

What Should You Do if Your Furnace Is Short Cycling?

If you suspect that your furnace has cycling issues, try these furnace troubleshooting steps. For starters, you should:

1. Replace your filter. The most likely culprit of short cycling is a filthy filter. A clogged filter can block the flow of cool air—something that your furnace needs so that it doesn’t overheat. For best performance, change your air furnace filters once a month during high-usage months.
2. Check the power. Have you lost power? Electricity is needed to run your furnace—even if you have a natural gas furnace. If your lights are back on but the heat is not, your furnace might just need a restart; some furnaces automatically shut down when power is lost. But if you’re still dancing in the dark, give your electrical company a call. 
3. Check the thermostat batteries and settings. Batteries go dead, and thermostats go bad, so give them a close look if a new filter doesn’t fix things. Make sure your thermostat is on and set it to “heat.”
   
   You can test the connection to the furnace by increasing the temperature a few degrees. If the thermostat is functioning correctly, the furnace should immediately turn on. If it doesn’t work, it might be time for more comprehensive thermostat testing or a new thermostat. 
4. Call a repair technician. If you’re still experiencing problems, give your local heating expert a call. Most repairs will cost less than $400. But if your furnace is over 15 years old and reaching the end of its life, repairs may periodically run over $1,000.
   
   In this situation, you may want to consider purchasing a high-efficiency furnace to reduce both ongoing repair costs and your heating bills. 

Don’t Let Short Cycling Short-Change Your Relationship with Your Furnace 

Whether you need your furnace fixed or to replace your furnace, we’ll make sure that your furnace that will be on-again, off-again at just the right frequency. 

If you live in the Twin Cities area, call us at 612-825-6867.