Normal Cycling vs. Short-Cycling Furnaces


Normal Cycling vs. Short-Cycling Furnaces

Normal Cycling vs. Short-Cycling Furnaces

Normal Cycling vs. Short-Cycling Furnaces

Way back in the early days of HVAC, the game was simple: heat your home as fast as possible. Naturally, that meant installing the biggest and baddest equipment. And while that may have been effective, it certainly wasn’t cheap.

Now, we know that the best approach is one that balances power and efficiency. That’s why your furnace will naturally cycle on and off. Instead of blasting hot air continuously, it uses cycles to gradually warm the entire home. This also keeps it warmer longer, too.

So if your furnace is rapidly turning on and off, that can be a huge problem. It’s called short-cycling, and here’s what you have to know about it:

Normal Cycling

The process for normal cycling goes like this:

  1. You set the thermostat to the desired temperature.
  2. Fuel is supplied, the burners are lit, and the fuel is combusted into hot air.
  3. The blower fan blows that hot air through the ducts and into the home.

This cycle lasts about 15 minutes, which is the ideal amount of time it takes for the entire home to get just a bit warmer. These cycles are then repeated until the home is heated to the temperature on the thermostat.

Ideally, the cycles are timed so that you can get the most out of your furnace with the least amount of energy expended.


Instead of slow and gradual cycles, short-cycling is what happens when the furnace shuts on and off rapidly. This is bad for several reasons:

  • Your home takes forever to heat up: Since the furnace can’t go through a full cycle, it takes much longer for the home to reach your desired temperature.
  • It’s going to drive up your heating bill: Operating longer than necessary means unnecessary amounts of energy used up.
  • It can damage the furnace over time: Starting up the furnace is more intense than running it continuously; repeated startup cycles puts a lot of stress on the furnace’s components.

What Causes Short-Cycling?

Without a thorough inspection of your furnace, it’s hard to determine the exact cause of your short-cycling issues. However, here are some of the most common causes:

  • The unit is too powerful for the home: When a furnace is installed, its size and output must be chosen according to a series of load calculations. This ensures that you’re getting the perfect furnace for your home. If your HVAC technician overestimated the size, the furnace might be too powerful. This is one of the main reasons that furnaces short-cycle.
  • The unit is overheating: On the other hand, your unit might simply need a maintenance check. There might be a broken or malfunctioning component that’s causing the furnace to overheat. You can also try checking if the air filter has been changed recently.
  • Thermostat problems: A thermostat that’s malfunctioning or has been installed in a bad location could be triggering

If your furnace is short-cycling, your best bet is to call up a heating expert in Colorado Springs. They’ll be able to get to the bottom of the issue and tell you how to proceed.


We are following all local guidelines regarding masks, distancing, sanitary practices, etc. Call (719) 573-9794 for more information on how we are preventing the spread.

Font Resize