What Is The Typical Run Time For A Furnace?

If your furnace is operating correctly, it should cycle about 2 to 3 times per hour. How long it operates depends on how cold it is outside. In milder temperatures, it may run for 10 to 15 minutes. The colder it gets, the longer the run cycle will be.

If your furnace isn’t working correctly, it may start running more frequently. If you notice your furnace turns on and off frequently, it’s called short cycling and that can make your home less energy efficient. Before you call us for furnace repairs in Denver Metro, take a look at the signs and symptoms of furnace short cycling.

Why Is My Furnace Short Cycling?

In general, furnace short cycling is caused by one of three things.


Your gas furnace has a heat exchanger that heats the air supply that flows into your home. If this overheats, it will shut down to protect the components from further damage. As the heat exchanger cools, it’ll turn back on to attempt to heat your home. This creates an endless cycle of turning on and off.

The problem lies with creating too much heat inside the furnace. With this amount of buildup in your furnace, it runs the risk of ruining the heat exchanger, which can run into the thousands of dollars depending on your system. This is usually caused by:

  • Dirty air filters
  • Closed registers or vents
  • Blocked registers or vents
  • Blocked exhaust pipes

All can be potentially dangerous to your furnace, so it’s important to get them fixed as soon as possible to prevent your furnace


short cycling furnace fix

The thermostat controls how often your furnace will turn on and off. Think of it as the brain of your system to tell it what temperature your home should be. If it malfunctions, it may cause your furnace to operate incorrectly.

Take a look at your thermostat – does it appear to be working correctly? Does the display light up? Does the temperature readings change as the furnace turns on and off?

You should also look at the thermostat location. Is it near a register? Is it near a window that allows sunlight to filter onto it and cause false readings? If you have a question, a professional can help you determine if it’s set up correctly.

Oversized Furnace

Do you have a new furnace? If the contractor installed a unit too big for your home, it could be short cycling.

Furnaces are sized according to how much heat it can put out in an hour. If the system is too big, it will heat that level too quickly, short cycling as it reaches the desired temperature.

This often happens with “good deals” – where a technician doesn’t perform proper testing to make sure they install the correct size of furnace.

Unfortunately, if you don’t have a proper warranty in place that allows the company to come back out and install the correct size, the cost may be on you. But in the long run, a proper sized furnace will operate better, provide proper energy efficiency, and heat your home to a comfortable level.

More Furnace Short Cycling Questions? Call The Metro Denver Furnace Experts at Quality First Service Group!

Have additional questions about how frequently your furnace runs? Give the Metro Denver furnace repair experts at Quality First Service Group a call today. Based in Metro Denver, we proudly serve customers in Parker, Littleton, Castle Rock, and the surrounding areas.

You can count on Quality First

From start to finish, we go the extra mile for our customers.

Simple, friendly scheduling

We're here to help. Get an appointment time that fits your busy schedule.

Service experts, not salespeople

Our goal is to get your problem fixed, at the budget that works for you.

Know your technician

We will send a photo of your tech before the appointment along with live GPS tracking updates.
DENVER METRO (720) 772-5081
CASTLE ROCK (720) 325-1371

Helping people is our passion


We believe in giving back

As a family business owned by Colorado locals, we are committed to our community. That's why we support and provide free services to charities and nonprofits across the Front Range.