Why Won’t My Furnace Keep Up? Common Reasons And Solutions

Why Won’t My Furnace Stay Lit? Granbury, TX
Why Won’t My Furnace Stay Lit? Granbury, TX from actexasmade.com


During the cold winter months, a properly functioning furnace is crucial for keeping your home warm and comfortable. However, it can be frustrating when your furnace fails to keep up with the desired temperature, leaving you shivering. In this article, we will explore some common reasons why your furnace may struggle to keep up and provide possible solutions to help you resolve the issue.

1. Incorrect Thermostat Settings

One of the most common reasons for a furnace not keeping up is incorrect thermostat settings. Ensure that your thermostat is set to the desired temperature and the fan is set to “Auto.” Sometimes, the thermostat may also need a battery replacement, so check if the batteries are functioning properly.

2. Dirty Air Filters

A clogged or dirty air filter can restrict the airflow, causing your furnace to work harder and struggle to maintain the desired temperature. Check your furnace’s air filter and replace it if it appears dirty or clogged. Regularly changing the air filter can significantly improve your furnace’s performance.

3. Obstructed Vents and Registers

Blocked or closed vents and registers can disrupt the airflow, leading to uneven heating or inadequate heat distribution throughout your home. Ensure that all vents and registers are open and unobstructed to allow proper airflow. Additionally, make sure furniture or other objects are not blocking the vents.

4. Leaky Ductwork

Leaky ductwork can cause heated air to escape before it reaches the desired areas of your home. Inspect your ductwork for any leaks or gaps and seal them properly. Consider hiring a professional to perform a thorough inspection and repair any significant ductwork issues.

5. Insufficient Insulation

If your home has inadequate insulation, it can lead to heat loss and make it challenging for your furnace to keep up. Check your home’s insulation and consider adding more if necessary. Proper insulation can help retain the heat generated by your furnace and improve its efficiency.

6. Furnace Size Mismatch

If your furnace is too small for your home’s heating needs, it will struggle to keep up with the desired temperature. Consult with a heating professional to ensure that your furnace is appropriately sized for your home. Upgrading to a larger furnace may be necessary to achieve the desired heating capacity.

7. Faulty Ignition System

A malfunctioning ignition system can prevent your furnace from igniting or cause frequent system shutdowns. If you suspect an issue with the ignition system, it is best to call a professional technician to inspect and repair it. Ignoring this problem can lead to further damage and reduced furnace performance.

8. Overworked Furnace

If your furnace is constantly running without a break, it may be overworked and unable to keep up with the desired temperature. This could be due to an undersized furnace, inadequate insulation, or other underlying issues. Consult with a professional to determine the cause and find a suitable solution.

9. Lack of Maintenance

Regular maintenance is essential for keeping your furnace in optimal condition. Neglecting maintenance tasks like cleaning, lubricating, and inspecting can lead to decreased performance and efficiency. Schedule annual maintenance with a qualified technician to ensure that your furnace operates at its best.

10. Age and Wear

Finally, the age and wear of your furnace can impact its ability to keep up with the desired temperature. Older furnaces may struggle to maintain consistent heat output and may require more frequent repairs. If your furnace is old and frequently breaking down, it may be time to consider a replacement for better performance and energy efficiency.


When your furnace fails to keep up with the desired temperature, it can be frustrating and uncomfortable. By identifying the possible reasons and implementing the appropriate solutions discussed in this article, you can improve your furnace’s performance and ensure a cozy and warm home during the colder months.