Why Your Furnace Is Running Constantly During Freezing Temperatures

When winter temperatures drop below freezing, your furnace has to work even harder to heat your home and keep you comfortable. This means you can expect your furnace’s heating cycles to last longer as it will need to produce more heat to combat the extreme cold. However, your furnace should never run nonstop. If your furnace is running constantly with no break, you may be dealing with a larger issue.

In this blog, our HVAC experts at Cahill Heating, Cooling, Electric, Plumbing & Sewer explain why it’s a problem for your furnace to run constantly, what causes this, and how to solve the issue.

Why Your Furnace Should Not Run Constantly

Furnaces, especially those found in Chicago-area homes, are designed to be durable, as they need to be able to continue working even in extreme cold. However, even the best furnace needs to take a break. When your furnace runs constantly, it does not have the chance to recover between heating cycles. This causes increased wear and tear on your unit and the potential for overheating, which can lead to repairs and even system shutdowns. Constant runtimes can also significantly increase your energy bills, turning this into a costly issue.

5 Common Reasons Your Furnace Won’t Stop Running

Dirty Air Filter Restricting Airflow

One of the most common and easily fixable causes of long run times is a clogged air filter. A dirty filter restricts airflow, making your furnace work harder to circulate warm air throughout your home. This can cause:

• Longer heating cycles
• Reduced efficiency
• Increased wear and tear

Air filters should be replaced every one to three months to ensure your furnace continues to work efficiently.

Thermostat Issues

Sometimes the furnace isn’t the problem, it’s actually your thermostat. Whenever you are experiencing heating issues of any kind, the thermostat is one of the first things to check. For a furnace that is constantly running, make sure the fan setting on your thermostat is set to “Auto,” not “On”. You should also check that your thermostat is accurately reading the room temperature. If your thermostat is registering that your home is colder than it actually is, it will tell your furnace to run for longer. This can happen if your thermostat is located near a draft, a window, or a particularly cold spot in your home.

Air Leaks or Poor Insulation

If warm air is constantly escaping your home, your furnace will run longer to compensate. Common culprits include:

• Drafty windows and doors
• Inadequate attic insulation
• Gaps in ductwork

In these cases, the furnace is doing its job, but your home isn’t holding onto the heat. Your furnace has to keep working to replenish the heat that is being lost, leading to constant runtimes.

Aging or Inefficient Furnace

As furnaces age, they gradually lose efficiency. Components wear down, internal buildup occurs, and performance declines. Older furnaces often have to run longer to achieve the desired home temperature than they would have when they were new. If your furnace is over 15 years old and struggling during cold weather, it may benefit from a professional inspection to assess its condition and determine if a furnace replacement is due.

Mechanical Problems

Certain internal issues with your furnace’s components can also cause constant operation, such as:

• Blower motor problems
• Flame sensor issues
• Ignition malfunctions
• Ductwork blockages

These are not DIY fixes. A licensed technician can accurately diagnose and resolve the issue before it leads to a breakdown.

What To Do If Your Furnace Is Running Constantly

If your furnace is running nonstop, there are a few simple troubleshooting steps you can take to try and solve the problem. First, verify your thermostat is set correctly, that the fan is on “Auto,” not “On”, and that it’s reading your home temperature correctly. If the settings are correct, but your thermostat isn’t showing the right interior temperature, you’ll need to reach out to a professional HVAC company to discuss relocating your thermostat.

If the thermostat is working properly, move on to your air filter. Replacing dirty or clogged air filters can often solve this problem. You should also go around your home and seal any air leaks around windows or doors.

If you have tried the above steps and they have not solved the problem, it’s time to reach out to the professionals. Solving more complex issues, like blower motor problems or needing to replace a furnace, are not DIY projects. Our heating technicians at Cahill can inspect your furnace to accurately diagnose the problem and provide the needed furnace repairs.

Schedule Furnace Services in the Greater Chicago Area

When you need a trusted team to solve your furnace problems, Cahill Heating, Cooling, Electric, Plumbing & Sewer is the HVAC company to call. We have served homeowners throughout the greater Chicago area since 1973, and our decades of experience have given us a unique understanding of local heating needs. Our factory-trained technicians work efficiently to restore your comfort, and we even provide same-day appointments and 24/7 emergency services for urgent issues.

Call Cahill today to schedule furnace repairs in the greater Chicago area.