Why is My Furnace Not Turning On?


There’s nothing quite as frustrating as coming home to a cold house and realizing your furnace isn’t turning on. A functioning furnace is crucial to keeping your home comfortable during colder months, so it’s essential to troubleshoot and resolve the problem as soon as possible.

There are several potential reasons why your furnace may not be turning on. In this article, we’ll discuss common troubleshooting steps to help you identify and resolve the issue.

Key Takeaways

  • A furnace not turning on can be caused by several issues, including thermostat settings, power supply, or a dirty air filter.
  • Checking and adjusting the thermostat settings, inspecting the power supply, and cleaning or replacing the air filter are simple troubleshooting steps you can take.
  • For gas furnaces, it’s also essential to check the pilot light and gas supply.
  • Scheduling professional maintenance and contacting a professional for further diagnosis are recommended if troubleshooting steps do not solve the problem.

Check the Thermostat Settings

If your furnace is not turning on, the first thing you should check is your thermostat settings. Make sure that your thermostat is set to “heat” and that the temperature is set higher than the current temperature in your home. If your thermostat is battery-powered, replace the batteries to ensure it has proper power.

If your thermostat settings are correct but your furnace is still not responding, try turning the thermostat up a few degrees. Sometimes, the temperature difference may not be significant enough to trigger the furnace to turn on.

If you have a programmable thermostat, check the schedule and ensure that it corresponds with your expected heating needs. A mismatch between the schedule and your routine may lead to the furnace not responding to the desired temperature.

If you have an older thermostat, it may be time for an upgrade. A newer thermostat with smart features can save energy and provide more accurate temperature control.

Inspect the Power Supply

If your furnace is not getting power, the first step in troubleshooting is to inspect the power supply. Often, the problem can be easily resolved by checking a few key components.

Important Note: Before inspecting the power supply, make sure to turn off the furnace and disconnect it from the power source to avoid any potential safety hazards.

Step Description
Step 1 Check the circuit breaker. If the breaker is tripped, turn it off and then back on to reset it. If it keeps tripping, contact an electrician.
Step 2 Ensure the furnace is properly plugged in. If it is not, securely plug it in and try turning it on again.
Step 3 Confirm that the fuse is not blown. If it is, replace it with a new one of the same amperage.

If you have completed these steps and your furnace is still not getting power, it may be a more complex issue that requires the expertise of a professional technician. Avoid attempting any repairs on your own to prevent further damage or safety risks.

Check the Pilot Light (For Gas Furnaces)

If you have a gas furnace, a common reason it may not be turning on is that the pilot light has gone out. The pilot light is a small flame that ignites the gas burner and starts the heating process. If the pilot light is out, the furnace won’t be able to ignite and heat your home.

To check the pilot light, locate the furnace’s access panel and remove it. Then, find the pilot light assembly, which should be near the bottom of the furnace. If the pilot light is out, follow the manufacturer’s instructions to relight it. Be sure to follow the safety precautions and use caution when handling gas appliances. If the pilot light won’t stay lit after several attempts, it may be a sign of a more significant issue, and you should contact a professional for assistance.

If the pilot light is lit, but the furnace still isn’t igniting, there may be other underlying issues. In this case, it’s best to contact a professional for further diagnosis and repair.

Keywords: gas furnace, pilot light, furnace not igniting.

Clean or Replace the Air Filter

A dirty or clogged air filter can cause a furnace to not work efficiently. The filter’s purpose is to trap dust, debris, and other particles, preventing them from circulating throughout your home. When the air filter becomes overloaded, it obstructs the system’s airflow, causing the furnace to work harder than necessary.

To clean or replace the air filter, first, locate the filter. In most cases, it’s located within the furnace or the return air duct. Once you’ve found the filter, remove it and assess its condition.

If the filter is dirty, clean it by vacuuming it or washing it with soap and water. If it’s damaged or worn out, replace it with a new one. Make sure to choose the correct filter size for your furnace.

For optimal performance, it’s recommended to clean or replace the air filter every 1-3 months, depending on usage. By doing so, you’ll improve your furnace’s efficiency and prolong its lifespan.

Keep in mind that a furnace not working efficiently can also be a symptom of other underlying issues. If cleaning or replacing the air filter doesn’t resolve the problem, consider contacting a professional for further diagnosis and repair.

Check for Blocked Vents and Registers

Blocked vents and registers can significantly affect the airflow of your furnace. This can lead to inefficient heating and cause the furnace to shut off. To ensure a consistent and unobstructed flow of air, it’s important to inspect and clear any obstructions from your vents and registers.

The first step is to check all the vents and registers in your home and make sure they’re open and free of any debris or dust. If you notice any obstructions, use a vacuum cleaner or a brush to clean them out. It’s crucial to maintain clear pathways for efficient heating.

If you have a furnace with a filter, it’s essential to check and clean it regularly. A dirty or clogged filter can cause malfunctions in your furnace and impact its airflow. It’s recommended to clean or replace the filter every three months, depending on usage.

If you’ve checked all the vents and registers and cleaned the filter, but your furnace is still not turning on, it’s best to contact a professional technician for further assistance. They can diagnose and resolve any underlying issues that may be causing the problem.

Verify the Gas Supply (For Gas Furnaces)

If you have a gas furnace and it’s not turning on, one possible issue could be with the gas supply. To verify this, start by checking the gas valve, which should be in the “on” position. If the valve is closed, turn it to the “on” position and try to restart the furnace.

If the valve is open and the furnace still isn’t receiving gas, contact your gas company to see if there is an interruption in your gas supply. Do not attempt any repairs on the gas supply yourself. This is a dangerous task that should only be performed by a professional technician.

To ensure the safety and optimal performance of your gas furnace, it’s essential to have it maintained regularly by a professional HVAC technician. They can detect and resolve potential issues before they become major problems.

If you’re experiencing issues with your gas furnace not receiving gas, it’s important to take action as soon as possible to prevent any potential hazards or damage. Contact a professional technician to schedule an inspection and resolve the issue promptly.

Schedule Professional Maintenance

While basic troubleshooting steps can often resolve a furnace not turning on, professional maintenance is essential for ensuring optimal performance and detecting any potential issues early on. It is recommended to schedule a furnace inspection at least once a year, ideally before the start of the heating season.

During the inspection, a trained technician will thoroughly assess your furnace system, including the heat exchanger, burner assembly, and safety controls. They will also clean and tune up the system, ensuring it runs efficiently and safely.

Professional maintenance can prevent costly repairs, extend the lifespan of your furnace, and keep your home comfortable throughout the winter. Don’t hesitate to schedule an appointment with a trusted HVAC technician to ensure your furnace is functioning at its best.

Consider Other Potential Issues

If you have tried all the troubleshooting steps mentioned above and your furnace still does not turn on, there may be other underlying issues. It is important to reach out to a professional for further diagnosis and repair. Attempting to fix complicated issues on your own can be dangerous and may cause further damage to your furnace.

Professional technicians have the expertise to identify and repair problems that may not be immediately apparent. They can address issues with the electrical wiring, ignition system, or other components that require specialized knowledge and tools.

Don’t delay in contacting a professional if you suspect there are additional furnace issues. Early detection and repair can save you money in the long run and prevent further damage to your furnace.


Congratulations! You’ve taken the first step in troubleshooting your furnace and resolving the frustrating issue of it not turning on. Remember, a functioning furnace is essential for a comfortable home, so don’t delay in taking action.

We’ve covered several potential causes for your furnace not turning on, including thermostat settings, power supply, pilot light (for gas furnaces), air filter, vents and registers, gas supply (for gas furnaces), and the importance of professional maintenance.

If you’ve gone through these troubleshooting steps and still can’t get your furnace to turn on, don’t panic. There may be other underlying issues that require a professional’s expertise to diagnose and resolve.

Don’t hesitate to contact a professional for further assistance!

Thank you for reading this article and taking the initiative to resolve your furnace issue. We hope these troubleshooting steps were helpful and encourage you to schedule regular professional maintenance to prevent future problems. Stay warm!

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