Troubleshooting Tips For Furnace Not Blowing Hot Air


We’ve all been there – the frustration of a furnace that’s working, but just won’t blow hot air. Don’t worry, we’re here to help you troubleshoot and fix the issue.

In this article, we’ll guide you through the steps to get your furnace back in action. From checking thermostat settings to inspecting the air filter and examining the blower motor, we’ve got you covered.

So let’s dive in and find out what could be causing your furnace woes!

Check the Thermostat Settings

Check if the thermostat is set to the correct temperature. Sometimes, when our furnace is not blowing hot air, it’s simply because the thermostat settings are off.

We all know how easy it is for someone in our household to accidentally change the temperature without realizing it. So, let’s take a moment to check that first.

To do this:

  • Locate the thermostat on the wall and check if it is displaying the desired temperature setting.
  • If not, adjust the temperature accordingly and wait a few minutes for the furnace to respond. Increasing or decreasing by a degree or two may help.
  • If adjusting the temperature does not solve the issue, check for any programming problems with the thermostat.
  • A glitch or accidental override could cause improper heating.
  • Try resetting the thermostat to default settings to see if that resolves the problem.

Inspect and Replace the Air Filter

Make sure you’re regularly replacing the air filter to ensure proper airflow and heating in your furnace. At first, this task may seem trivial, but it plays a crucial role in maintaining the efficiency of your system.

Here are four reasons why regularly inspecting and replacing the air filter is important:

  • Improved Air Quality: A clean air filter traps dust, pollen, pet dander, and other airborne particles. By regularly changing it, you can significantly improve the indoor air quality in your home.
  • Enhanced Furnace Efficiency: When an air filter becomes dirty and clogged, it restricts airflow to your furnace. As a result, your furnace has to work harder to heat your home. By regularly replacing the filter, you allow for proper airflow and help keep your furnace running efficiently.
  • Longer Furnace Lifespan: A dirty air filter puts unnecessary strain on your furnace’s components. Over time, this can lead to premature wear and tear and potentially shorten its lifespan. By regularly replacing the air filter, you can extend the life of your furnace.
  • Energy Savings: An inefficiently running furnace consumes more energy than necessary to maintain desired temperatures in your home. By ensuring proper airflow with a clean air filter, you can reduce energy consumption and save money on utility bills.

Verify the Pilot Light or Ignition System

Ensure that you regularly verify the pilot light or ignition system to guarantee the proper functioning of your furnace. The pilot light or ignition system is crucial for igniting the fuel and starting the heating process in your furnace.

By regularly checking and maintaining these components, you can prevent issues like a furnace that works but won’t blow hot air.

To do this:

  • Locate the pilot light or ignition system on your furnace. It is usually found near the burner assembly.
  • If you have a pilot light, make sure it is lit and burning steadily with a blue flame. If it goes out frequently, there may be an underlying issue that needs to be addressed.
  • If your furnace has an electronic ignition system, check for any error codes displayed on the control panel. These codes can provide valuable information about potential problems.
  • In addition to visual inspections, listen for any abnormal sounds coming from the combustion chamber when your furnace starts up. Unusual noises could indicate an issue.
  • Regularly verifying these components will help ensure efficient and reliable operation, providing warm air when you need it most.
  • Don’t underestimate the importance of proper maintenance in keeping your home comfortable during colder months.

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Examine the Blower Motor and Belt

To properly examine the blower motor and belt, we should first:

  • Locate them on our furnace. The blower motor is typically inside the furnace cabinet, while the belt connects the motor to the blower wheel.
  • Turn off the power to the furnace before inspecting these components.

Once located, we can:

  • Visually inspect the blower motor for any damage or wear. Look for frayed wires, loose connections, or excessive dirt and debris.
  • Check if the motor spins freely by giving it a gentle push. If it feels stiff or doesn’t move, there may be an issue needing attention.
  • Examine the belt for any wear or damage. Check for cracks, fraying, or excessive slackness.
  • A loose or worn-out belt can affect airflow and efficiency.
  • Contact a professional HVAC technician for assistance if any problems are noticed during the inspection. They have the expertise to diagnose and resolve issues effectively.

Remember that regular maintenance of these components is essential for smooth and efficient operation over time.

Ensure Proper Ductwork and Airflow

Check if the ductwork is properly installed and that there is adequate airflow throughout your heating system. This is an important step to ensure that your furnace can effectively distribute hot air throughout your home. Improperly installed ductwork or restricted airflow can lead to a lack of heat being delivered to each room, resulting in a furnace that works but doesn’t blow hot air.

To help you understand the importance of proper ductwork and airflow, here’s a table highlighting some potential issues and their corresponding effects:

Blocked or disconnected ductsUneven heating; reduced airflow
Leaky ductsEnergy loss; decreased efficiency
Clogged filtersRestricted airflow; poor air quality 

As you can see, any of these problems can greatly impact the performance of your heating system. If you suspect an issue with your ductwork, it’s best to call a professional HVAC technician who can assess the situation and make any necessary repairs or adjustments.

Furnace Doesn’t Blow Hot Air – FAQ

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What are some common thermostat settings to check when the furnace is not blowing hot air?

When the furnace is not blowing hot air, there are several common thermostat settings to check.

First, ensure that the thermostat is set to heat mode and the desired temperature is higher than the current room temperature.

Next, make sure that the fan setting is on ‘auto’ or ‘on,’ as it should be set to ‘on’ for the furnace to blow hot air continuously.

Additionally, check if there are any programming or scheduling issues with the thermostat that may be affecting its operation.

How often should the air filter be inspected and replaced?

We should inspect and replace the air filter regularly to ensure the proper functioning of the furnace.

The frequency of inspection and replacement depends on various factors such as the type of filter, usage, and indoor air quality.
As a general guideline, it is recommended to inspect the air filter every 1-3 months and replace it as needed.

This helps maintain good airflow, improves energy efficiency, and prevents potential issues with the furnace’s performance.

What are the possible reasons for a malfunctioning pilot light or ignition system?

Possible reasons for a malfunctioning pilot light or ignition system can include:

– A dirty or clogged pilot tube
– A faulty thermocouple
– A worn-out pilot assembly
– An issue with the gas supply

It is also possible that there may be an electrical problem causing the ignition system to malfunction.

In any case, it is important to have a professional HVAC technician inspect and repair the pilot light or ignition system to ensure the proper functioning of your furnace.

How can I tell if the blower motor or belt needs to be examined or replaced?

To determine if the blower motor or belt needs to be examined or replaced, we can conduct a few simple checks:

– Listen for any unusual noises coming from the furnace while it is running.
– Visually inspect the belt for signs of wear or damage.
– If these initial assessments don’t reveal any issues, call a professional technician to further diagnose and address the problem.

What are some signs of improper ductwork or airflow that could be affecting the furnace’s ability to blow hot air?

Some signs of improper ductwork or airflow that could affect the furnace’s ability to blow hot air include weak or uneven airflow throughout the house, rooms not reaching desired temperatures, excessive dust buildup around vents, and unusual noises coming from the ducts.

These issues can be caused by blocked or leaky ducts, incorrectly sized ductwork, or obstructions in the system.

It is important to have a professional inspect and address these problems to ensure optimal heating performance.


So, if you find yourself in a situation where your furnace is working but not blowing hot air, don’t panic! Start by checking the thermostat settings to ensure they are correct. Then, inspect and replace the air filter if needed. Make sure to verify the pilot light or ignition system to ensure proper functioning. Examine the blower motor and belt for any issues that may be causing the lack of hot air. Lastly, ensure that your ductwork and airflow are properly set up.

By following these steps, you should be able to troubleshoot and resolve the issue with your furnace efficiently. If not, call a professional furnace repair company like ALP Heating. Stay warm!

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