How Often Should My Furnace Turn On and Off?

how often should my furnace turn on and off

In the dead of winter, how often should my furnace turn on and off? It’s not uncommon to notice your heating unit consistently cycling, but at a certain point, it may be a cause for concern. 

Constant cycling can drive up your monthly energy costs. An overworked furnace also causes more wear and tear on the components by putting undue strain on your heating unit.

Learn more below about the normal furnace cycle and why it could go wrong, as shared by JC Heating & Cooling, Western Springs’ trusted furnace repair company.

What Does Normal Cycling Look Like For Your Furnace?

Under normal circumstances, a furnace will run for 10 to 15 minutes across two to three cycles per hour. In homes with insulation, this timeframe should be enough to heat all the rooms.

However, two factors primarily impact this cycling:

  • Outside temperature: When temperatures drop exceedingly low, your unit might cycle more, especially where there is poor insulation.
  • Home structure: The architecture of your home affects how your unit runs. Homes with a lot of open space, such as large rooms or high ceilings, take longer to heat. To warm these areas, the unit will need to run more often.

6 Reasons Your Heating Unit Keeps Turning On and Off

A furnace turning on and off more than three times in an hour or running for less than 10 minutes indicates a problem. What’s causing your heater to cycle over and over again? The following are some of the most common causes of a short-cycling furnace:

1 A Faulty Thermostat

The thermostat acts as the control center for your furnace, telling it when to run and for how long. When there’s something wrong with the thermostat, it causes bizarre cycling patterns.

Another thermostat concern is its location. Thermostat fixtures near heating sources, such as ovens or direct sunlight, might not properly gauge the temperature. They’ll then signal the system to heat the space again to try and correct the issue, even though the temperature is at the right level.

2 A Dirty Furnace Filter

A clogged furnace filter blocks proper airflow and prevents the unit from working correctly. This causes inconsistent cycling and overheating, which is a dangerous problem in a furnace. Be sure to have an HVAC technician like JC Heating & Cooling check things before running your furnace at the start of the season.

3 An Oversized Heating System

Sometimes, a heating unit just isn’t the right match for the house it’s in. An oversized (or undersized) system means inadequate heating. Units that are too large typically short cycle.

4 An Outdated Unit

How often should my furnace turn on and off if it’s getting on a bit? Furnaces last about 15 to 20 years on average, and older units don’t work as well. If you’ve had your heating unit for more than ten years, it’s probably showing multiple signs of wear, including constant cycling. 

Other signs that it’s time for a new heater installation are loud noises and inadequate heating. 

5 A Dirty Flame Sensor

The flame sensor is an essential part of your heating unit, helping regulate cycles. If this sensor is dirty, it can’t check for the presence of a flame within the unit, and it will keep on turning on and off. This is also a safety hazard, as it increases the risk of a fire.

6 Incorrect Duct Configuration

Ducts allow airflow into your heating unit and then outward to heat your home. An incorrect configuration affects airflow, making the unit work harder and causing constant starting, stopping, and brief cycles.

Could Your House Be Causing Furnace Short Cycling?

In some cases, constant heating cycles have nothing to do with the furnace itself. For example, certain structural characteristics make it harder for your furnace to adequately warm the home, such as:

  • High ceilings
  • Single-pane windows
  • Weak insulation
  • Open doors or windows

When the weather is particularly frigid, your furnace has to work against these types of features to keep your home toasty. While there isn’t anything wrong with your furnace, it is never helpful when the unit is working harder to do its job, particularly if you’re trying to minimize energy costs and delay an early replacement. Installing a different unit that fits better might help.

When Is It Time To Repair Your Furnace?

How often should my furnace turn on and off, and how do you know whether it needs some extra attention in between? A broken heater will show obvious signs of distress on top of short cycling, such as:

  • Unusual noises: A heater makes noises when it starts and stops, but it shouldn’t be noisy throughout the entire cycle. Strange or very loud noises are a cause for concern.
  • Difficult startup: Does it take a while for your furnace to get going after you turn it on? Efficient machines run quickly upon activation, so yours might be outdated or in urgent need of servicing.
  • Inconsistent heating: Hot or cold spots suggest a furnace problem. Your heating unit should provide equal heat distribution throughout all the rooms in your home.

Bad odors: If your heater produces a strange smell or gas odor when in use, switch it off and contact an HVAC professional like JC Heating & Cooling immediately. You could have a gas leak.

Professional heating services can address most of these issues. If a furnace is beyond repair or has severe damage, a replacement unit may solve your unit’s constant cycling problem.

Is Your Heater Constantly Cycling? Call The Professionals at JC Heating & Cooling Today!

If you’re still unsure about how often your furnace should turn on and off, there’s no reason to panic; JC Heating & Cooling’s technicians provide a wide variety of HVAC services in Hodgkins, Illinois, and the surrounding areas. 

How often should my furnace turn on and off in a full cycle? Learn all this and more when you contact JC Heating & Cooling about topics from how a furnace works with an AC unit to which HVAC models are currently the most energy efficient. Connect with us online or call 708-367-3199 today!