How Often Should a Furnace Cycle During Winter?

 

The coldest days of winter can put a strain on your furnace. While your unit may normally cycle on and off a few times every hour, you may also notice your furnace cycling more frequently when the temperature drops.

While cycling is normal, frequent cycling can indicate that your heating is struggling to keep up. We’ve put together this guide to help you understand the difference between normal furnace cycling and short cycling.

Understanding Furnace Cycling & Short Cycling

Is It Normal For a Furnace to Turn On and Off?

While it’s normal for your furnace to turn on and off repeatedly over the course of a day, cycling too often, known as short cycling, can indicate a problem with your heating system.

What is Furnace Short Cycling?

If your furnace is turning on and off every few minutes, this is known as short cycling. Short cycling typically indicates something is wrong with your heater. The problem can be anything from a dirty air filter to a broken motor. It’s best to get these issues looked at by an HVAC specialist as soon as possible.

How Often Should My Furnace Kick On?

Your furnace will typically kick on three to eight times every hour. How often your heat cycles will depend on the size of your home, the size of your unit, and how well-maintained your HVAC system is. While some variation in cycle time is normal, if your furnace is coming on significantly more or less than usual, it’s probably time to call in a heating repair expert.

How Often Should the Heat Kick On on Cold Days?

It’s common for your furnace to kick on more frequently in cold weather. While it’s okay if your furnace cycles on and off several times every hour, it shouldn’t cycle on and off more than 8-10 times. If it does, this is known as short cycling, and it’s a sign that something in your heating system needs to be fixed.

How Often Should a Furnace Run Each Cycle?

What’s a Typical Furnace Run Time?

A typical furnace run time is between 10 and 15 minutes. Although some models may run for as long as 20 minutes at a time. If you notice your furnace running for longer than 20 minutes each cycle, this may be a sign it’s working overtime to heat your home.

Furnaces that cycle for extended periods of time run the risk of overheating or wearing out more quickly than anticipated. If your system is cycling for longer than 20 minutes, call an HVAC professional for an inspection.

How Many Times Should a Furnace Cycle in an Hour?

In general, a working furnace will kick on anywhere from 3 to 8 times each hour. However, this number will vary greatly depending on the insulation in your home, the size of your home, and the outside temperature.

How Long Should a Furnace Run Before Shutting Off?

Your furnace will typically run for 10 to 15 minutes before shutting off. In some cases, your heat cycle may last for up to 20 minutes. If your furnace runs any longer than this, it’s likely struggling to heat your home properly. If your furnace only runs for a few minutes before shutting off, this can also indicate a problem.

Why is My Furnace Cycling On and Off?

Your furnace may be short cycling for a number of reasons, but the best way to diagnose the issue is to call an HVAC technician for repairs. You may have an improperly sized unit, a heater that’s past its prime, or issues with your thermostat or flame sensor. Here’s an overview of the most common short cycling issues.

Wrong-Sized Furnace

Unfortunately, a bigger furnace doesn’t always solve your heating woes. If you have a furnace that’s too large for the size of your home, it can lead to short cycling and uneven heating.

Most experts recommend 12,000 BTU for every 400-500 square feet within your home. However, this number can change dramatically depending on the climate and how well your home is insulated. It’s best to have an HVAC technician calculate the correct furnace size for your needs.

Overheating

When a furnace’s airflow is restricted, it can lead to overheating within the unit itself. This issue is typically caused by a dirty air filter, faulty heat exchanger, clogged air filter, or debris in your air ducts.

Thermostat Issues

In some cases, your furnace may be in good shape, but your thermostat is sending incorrect signals back to the unit. If your thermostat breaks or reads the wrong temperature, it can lead to your furnace short cycling.

Dirty Flame Sensor

If your furnace only clicks on for a few seconds at a time, it may have a dirty or malfunctioning flame sensor. Having an HVAC technician clean this sensor is the best way to fix short cycling issues.

Clogged Flue

When pests or debris get caught in your flue or vent pipe, your furnace will shut off automatically to protect your home from carbon monoxide poisoning. These types of flue clogs can cause short cycling.

Air Leaks

If your home is poorly insulated, your furnace may need to work harder to heat your home. This can lead to frequent cycling as your furnace strains to raise the temperature.

Old Age

As a furnace ages, it may begin to struggle to heat your home efficiently. This can lead to short cycling. If your furnace is over 10 years old, it’s likely time to think about a replacement.

Stop Furnace Short Cycling Once and For All

When you need reliable furnace repairs, trust the experts at Roth Home. Our technicians have the experience necessary to accurately diagnose your unit and make effective, long-lasting repairs. We’re the top choice for furnace repair in Portland and the surrounding areas.

Call our residential heating team today at (503) 994-5917 to schedule furnace repair service.