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Common Causes of an HVAC Not Blowing Hot Air

residential home in huntsville alabama

If you're wondering why your house is cold even though your furnace is running, your not alone. Many people face this issue more often than you make think. According to a report in 2019 by Consumer Repairs, 20% of people reported issues with their heating systems. Unfortunately though, when your HVAC is not blowing hot air, it is a common issue that can be difficult to diagnose and fix.

There are several potential causes of this problem, from blocked ducts to faulty components. To help those experiencing HVAC issues with no hot air, we've put together an overview of the common causes and possible solutions for this frustrating problem. So hopefully this guide will help you quickly identify the issues going on so that you can heat your home back up as soon as possible.

Let's get right into it!

The Most Common Causes of an HVAC Not Blowing Hot Air

When your HVAC isn't blowing hot air, it's likely that there is an issue somewhere in the furnace system itself. However, it is important to note that that is not always the case. It could be due to other issues outside of the unit itself. So it's important to understand all of the common causes and work through each one so that you can correctly identify the issue.

If the problem isn't the blower, there are other ways to tell if your HVAC needs attention.

With that being said, let's take a look at some of the most common causes of this problem:

Dirty Air Filter

If your HVAC is not blowing hot air, one of the first places you should check is the air filter. A dirty air filter can block airflow and cause your HVAC to work harder than it needs to, which can lead to a variety of problems including reduced efficiency and increased wear and tear.

To prevent this, be sure to check your air filter regularly and change it as needed. Depending on the type of system you have and the environment in which it operates, you may need to change your air filter as often as every month or two. If you're not sure how often to change your air filter, consult your owner's manual or contact a qualified HVAC technician for assistance.

woman resetting her HVAC thermostat to blow hot air

Malfunctioning Thermostat

Thermostats are responsible for regulating the temperature in your home, and if they are not working properly, your HVAC system will not be able to maintain a comfortable temperature. There are a few things that can cause a thermostat to malfunction, such as improper installation, loose wires, old and needs replaced, or a faulty connection. If you think your thermostat might be the problem, you can try replacing the batteries or checking the wires to see if they are loose. If neither of these solutions works, you may need to replace your thermostat.

When the thermostat malfunctions, it won't be able to accurately measure the temperature of the air inside the house.

Tripped Circuit Breaker or Blown Fuse

When your HVAC unit is not blowing hot air, one of the first things you should check is whether or not the circuit breaker has tripped or if a fuse has blown. If either of these has happened, it means that there is an issue with the electrical supply to the HVAC unit. You will need to reset the circuit breaker or replace the fuse in order to restore power to the unit.

If the circuit breaker or fuse has been tripped or blown, it could prevent the HVAC from blowing hot air. It's also important to note that you may need an HVAC professional or electrician to come out and see why your HVAC unit has tripped. As you may have a serious malfunction with your unit or issues with your electricity.

hvac unit not blowing hot air

The High Limit Switch

The high limit switch is a safety device that shuts off the furnace if the air temperature gets too high. If your furnace stops working, it may be because the high limit switch has tripped. There are a few reasons why this might happen: -The temperature inside the furnace is too high, it could be due to a clogged filter, or there is something blocking the flow of air through the furnace. If you think the high limit switch has tripped, turn off the power to the furnace and call a heating technician for help.

Your Pilot Light

If your HVAC is not blowing hot air, it's very possible that your pilot light has gone out. A pilot light is a small flame that ignites the gas in your furnace, and without it, your furnace can't heat your home.

One common reason for a pilot light to go out is if the gas valve is turned off. If this is the case, simply turn the gas valve to the "on" position and relight the pilot light.

Another common reason for a pilot light to go out is if there is a draft in the area where the pilot light is located. This can happen if there are open windows or doors near the furnace. To fix this problem, you'll need to find and seal any openings in the area.

If neither of these solutions works, it's possible that there is something wrong with the actual pilot light itself. In this case, you'll need to contact a professional for help.

Burner Issues

If your home’s HVAC system is not blowing hot air, it could be due to a problem with the burner. The burner is responsible for heating the air that is sent through the ducts and into your home. If the burner is not working properly, the air will not be heated and your home will not be as comfortable as it should be. There are a few different things that can cause burner issues.

One of the most common is a dirty or clogged burner. If the burner is not cleaned on a regular basis, it can become filled with dirt and debris. This can prevent the flame from igniting properly or can cause the flame to be weak and ineffective.

common causes of an hvac unit not blowing hot air infographic

How to Fix an HVAC Not Blowing Hot Air

The most effective and recommended way to fix an HVAC not blowing hot air is to have a professional technician inspect the system and identify the issue. They will be able to diagnose the issue and provide a solution that best fits the problem.

In addition to calling a professional, there are a few things you can do on your own to try to get your HVAC back up and running.

Check the Air Filters

The first step is to check the air filters and replace them if they are dirty.

Check the Thermostat

Make sure to check the thermostat and ensure that it is set to the correct temperature.

Check the Circuit Breaker

Make sure to check the circuit breaker and ensure that it hasn't tripped or blown a fuse.

Suspected High Limit Switch

If you think that the problem is with your High Limit Switch, you'll need to contact a local HVAC professional

Check the Pilot Light

If the pilot light is not working, you'll need to check to see if there is a draft in the area where the pilot light is located. If there are no other obvious solutions, you'll need to replace the pilot light

Check the Burner

If the burner is not working, the first step is to check to see if there is any debris or dirt on the burner. If there is, it will need to be cleaned before the burner can be replaced.

Check for Leaks

Make sure to look for any water leaks that may be affecting the efficiency of the system

thomas hvac employee working on an hvac system that is not blowing hot air

Consider Regular Furnace Maintenance

If you're not regularly maintaining your furnace, it could be the reason your HVAC isn't blowing hot air. Dust and dirt can build up over time, causing your furnace to work less efficiently. This can lead to a number of problems.

To avoid this, be sure to schedule regular maintenance for your furnace. This will help ensure that it's always in top working condition. Not only will this improve the efficiency of your furnace, but it will also help prevent common problems like an HVAC not blowing hot air. Making furnace tune ups worth it.

Finding The Solution to Your HVAC Unit Blowing Hot Air

A malfunctioning HVAC unit can be both a nuisance and a cause for concern. Fortunately, the most common causes of an HVAC not blowing hot air can usually be solved quickly and easily, as long as you know what to look for.

Before calling in a professional, take these causes into consideration so that they don’t end up costing you more time and money than necessary. With proper maintenance and care of your heating system, it should run smoothly all year round! Regular maintenance is the best way to prevent heating and air conditioning problems from happening.

Our final recommendation for anyone with an HVAC system is to ensure you perform regular maintenance. Whether you do this on your own or hire a local professional. Ensuring that your unit is maintained can help prevent issues like these from ever happening as well as extending your HVAC system lifespan and its efficiency.

If you need further help with your HVAC units and would like to speak with a local HVAC professional, contact us here at Thomas Service Company, your local pros in Huntsville, Alabama.