A dirty air filter produces bad odors and can negatively affect your AC unit's performance. When your air filter is clogged with dirt and debris, it can restrict the airflow to your unit and cause it to overheat. This can lead to a burning smell coming from the vents.
Overheating Motor
The bearings in the fan can break down, causing the motor that powers the fan to overheat. If that happens, you'll smell a burning smell. Bad Capacitor The capacitor helps the motor run. When it has an issue, the motor can overheat, and create the burning smell you may be encountering.
If you notice that your air conditioner smells like it is burning or like gunpowder, turn off the system immediately and call the local fire department. Once your home is safe, call an expert for help.
Here are a few common types of burning smells you could smell coming through the air conditioner. Burning Rubber: A burning rubber smell might signal a problem with your A/C compressor, clutch, or a misaligned pulley. Either of these may cause the belt to drag, which could lead to a burning rubber smell.
Solution: If this is the first time you've noticed the burning smell, turn off your air conditioner and lubricate the bearings right away. This will hopefully prevent the motor from burning out completely so you can avoid replacing it.
Mould and mildew love moisture, so when there's excess moisture in the ducts and vents in your air conditioning system, it's creating the perfect environment for mould to grow. When air is blown through the vents or ducts, the musty smell will spread through your home.
Dirty Filter
If your air filter is clogged, these contaminants can get sucked into the blower and cause it to overheat. This can also lead to dirt and dust reaching the heat exchanger and heating up. Both of these will cause a burning smell and can be mostly avoided by changing your filter regularly.
Not Blowing Cold Air – The first sign of a bad compressor is typically warm air coming from the vents in your home. This is because the compressor's main job is to turn the refrigerant from a liquid to a gas.
On average, AC compressor costs range from $800 to $2,300, with most folks paying $1,200 for a new one. However, your price will vary depending on factors like the size and brand of your compressor. Before you schedule your replacement, read on to learn about all AC compressor cost factors.
What happens if your HVAC filter is dirty? A dirty HVAC filter restricts airflow, which can lead to poor system efficiency, increased energy costs, and wear and tear on the unit.
Keep an eye out for these signs that your capacitor is about to go, including: Burning Smell – This is a distinct, acrid electrical smell. Smoke – You might have visual evidence of an electrical burnout. Oozing Fluid – This can be present around the capacitor and circuit board.
Faulty wiring or an overheated appliance can have an odor that smells like burning plastic. If it's coming from your HVAC system, it could be from an overheated blower motor -- possibly due to heavy dust buildup or a clogged air filter.
Dirty, Clogged Air Filter
Mold can form on the filter and elsewhere within your AC, causing the musty, vinegary smell. Put a mask on and remove the air filter. If there are visible signs of mold, dispose of it properly and put in a new one.
If a burning smell comes from your AC unit, and a popping noise accompanies it, this is a sign of an electrical failure. An electrical failure can cause sparks and heat to build up, creating a burning smell. If you hear any popping noises coming from your AC unit, turn it off and call a technician right away.
Phantosmia is when a person smells something that is not actually there. The smells vary between individuals but are usually unpleasant, such as burnt toast, metallic, or chemical smells. Possible causes range from nasal polyps to a stroke. Phantosmia is also called a phantom smell or an olfactory hallucination.
How Often Do I Need to Change Out My Air Filter? Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.
Your air conditioner compressor should last the whole lifespan of your air conditioner, about twelve years or more if you choose a ClimateCare air conditioner. However, it might not last that long if your air conditioner is too small for the space it's cooling, or if you don't keep your air conditioner well-maintained.
The technician should be able to tell you if the compressor is (or is not) still under warranty. If you have to pay for labor and the compressor, chances are you're going to need to replace the entire outside unit because it would cost slightly more than replacing the compressor.
Homeowners insurance covers HVAC systems when the damage is a result of a covered disaster or peril, including high winds, fallen trees, theft, hail or even a fire. So if lightning strikes your unit and damages its electrical components, your homeowners insurance policy would probably cover it.
#5 - The Belt Drive Motor is Overheating
This might be causing the problem if: The burning smell from AC unit smells like burning rubber.
Your air conditioner compressor is making unusual noises: If your compressor is making a loud rattling, grinding, or clicking noise, this could be an indication that a piece has broken inside it. If it is more of a grinding noise, the compressor bearings might need to be replaced.
Airflow is lower: Lower airflow coming from the air conditioner often means a weakening compressor. The AC is overheating: Are you experiencing frequent circuit breaker trips when the AC is on? This often means the compressor motor is overheating and overloading the circuit breaker.
Worn Out Bearings
A motor's metal bearings produce high-pitched squealing noises when they start wearing out. Worn-out bearings strain motors and cause them to overheat, creating a burning smell. An HVAC technician can usually resolve this issue by lubricating the motor bearings.
One primary spot to check: the heating, ventilation and air conditioning (HVAC) ductwork. Checking the HVAC system will help determine if the odor is coming from it or traveling through it from another area. If the odor is coming through the HVAC equipment, you'll need to trace it back through the system.
Any of these could cause the belt to drag that causes the smell of burning rubber. In either case, you will need auto AC service. Burning plastic is associated with burning hoses, wires, or electrical shorts. If you detect burning plastic, have an AC inspection to determine the underlying cause.