Burning Smell from AC Unit (What It Is & How to Stop It!)
If you turn on the heating or the air conditioning and start to notice a burning smell from your AC unit, you’re probably understandably alarmed. Is the system broken? Does something need to be replaced? Is something burning? Is there anything I can do? Is the house in danger? All these questions and more will arise - after all, a potential house fire is no joke.
The good news is that it is very unlikely that a burning smell from your AC unit is the warning sign for a fire. There are numerous things that could be causing the smell, but they aren’t too dangerous as long as you pay attention and act quickly. You absolutely should not ignore a burning smell from your AC unit - so let’s take a look at all the different potential causes for this smell and what you should do about them.
Reasons for a Burning Smell from AC Unit
The dust from disuse is burning off
The air filter is clogged
The motor is overheating
The capacitor is broken
The belt-drive motor is overheating
The electrical components are broken
Together, we’ll go through each of these reasons for the burning smell from your AC unit and look at how you can diagnose the problem and solve it.
6 Reason for a Burning Smell from an AC Unit
#1 - The dust from disuse is burning off
This might be causing the problem if: You have gone several months without turning on the heating, and the smell occurs right when you do.
Dust and dirt are carried through the air and they build up in the HVAC systems in our homes. Thick layers of dust and lint can end up coating the filters, vents, and heating components. That’s why we do what we do! Get in touch with us for a free consultation about cleaning your HVAC system.
When it comes to a burning smell from AC unit, sometimes the build-up of dust on your heating components means that when the heat is turned back on, the dust burns off. The smell should quickly dissipate. If it persists, you may have one of the other problems on this list.
What to do to fix the problem: Get your HVAC system professionally checked and cleaned.
#2 - The Air Filter is Clogged
This might be causing the problem if: You haven’t changed your air filters in more than two months.
Air filters are put in place to catch the dirt and debris that come into your HVAC system and to prevent them from circling back into the air in your home. They need to be changed regularly - check out our guide on how often to change your air filters - and if they get clogged they make it difficult for air to circulate. This ends with your fan having to work much harder, which can lead to overheating and a burning smell from AC unit.
What to do to fix the problem: Change your AC filter.
#3 - The Motor is Overheating
This might be causing the problem if: You’ve changed the air filter and still smell the burning smell.
An overheating motor can cause a burning smell from the AC unit because over time, the bearings can start to wear out. Usually, this is solved by lubricating the bearings, but you might need to replace the whole thing if the problem has gone far enough.
What to do to fix the problem: Turn off your system and lubricate the bearings on your motor. If the burning smell from AC unit persists, you may have to replace the motor or look at some of the other options on this list.
#4 - The Capacitor is Broken
This might be causing the problem if: The burning smell from AC unit has a plastic smell and is stronger at the vents outside the house.
The capacitor is an AC unit component that helps the motor to run. If it breaks, it’s going to cause the motor to overheat and start to make that burning smell from AC unit.
What to do to fix the problem: This is an urgent issue - turn off the HVAC system and get a professional to replace your capacitor.
#5 - The Belt Drive Motor is Overheating
This might be causing the problem if: The burning smell from AC unit smells like burning rubber.
Some AC units have belt drives that power their blowers, and over time, the rubber belt drives can become worn down or even begin to melt. If the burning smell from AC unit smells rubbery, it’s likely time to replace your belt.
What to do to fix the problem: Replace the rubber bands in your belt drive blower.
#6 - The Electrical Components Are Broken
This might be causing the problem if: The burning smell from AC unit is plasticy or has a tinge of sulfur to it.
The electrical components in your HVAC system have a plastic casing around them, so if the bring smell from AC unit has a plasticy tinge, it may be that some of your wiring is overheating and malfunctioning. This is an urgent and potentially dangerous problem.
What to do to fix the problem: Turn off the power to your HVAC system and seek professional help immediately.
Solving the Burning Smell from AC Unit
As you can see, there are plenty of things that can cause that burning smell from AC unit. From a simple case of dust in the system to a full electrical malfunction, it’s important to figure out exactly what the issue is so that you can avoid having to replace expensive parts down the road. Hopefully, this blog has helped you identify your problem and take some crucial steps to getting your HVAC system back into working order. If you need any help with that, or if you’re thinking about preventing future HVAC problems by getting your vents cleaned by the professionals, get in touch for a free consultation! Remember, when it comes to home maintenance, prevention is so much better than cure.