The primary cause of a bad air conditioner smell is infrequent system cleaning. Dirty internal parts can be home to mould and mildew, which will inevitably breed bacteria and other things you don't want in your home. It's essential to have your air conditioning system routinely serviced and cleaned.
Clean the air filters
Cleaning or replacing dirty filters should help to reduce the dirty-sock smell coming from your air conditioner by limiting microbial growth.
Mildew. Mildew is the most common culprit when an AC smells bad. If you smell moldy air coming from your AC vents, mold or fungus are growing in or around your AC unit and can sometimes make their way into the ductwork itself.
Your air filters are your first line of defense against mold and bacteria build-up. If the smell doesn't go away, you should first clean or replace your filters. If your filters are new or cleaning doesn't improve the smell, contact your local Trane Comfort Specialist™ to clean and inspect your ductwork.
A burning odor from an HVAC unit is usually a sign of a faulty compressor, electrical wiring, or fan. These parts of the HVAC system are manufactured from an array of metals and chemicals. Therefore, exposure to such smells is potentially harmful to your health.
Getting a Moldy or Musty AC Smell? A stale and dingy smell is by far the most common and foul smell experienced from ACs. If your AC smells musty, the general cause is the accumulation of water in the drain pan or drip lines (or ducts in case of ducted systems), which can cause fungus or mildew to grow.
Refrigerant poisoning happens when a person inhales chemicals used in cooling appliances. Certain appliances, such as refrigerators, air conditioners, and freezers, contain chemicals called fluorinated hydrocarbons. People often refer to these chemicals as Freon, which is a leading brand name.
In short, a musty smell indicates bacterial growth build-up, which forms on the drain, evaporator coil, or in the drip pan or drain line of your AC. Your evaporator coil is a dark and humid location, so all sorts of mold and mildew can grow, which causes that unpleasant, musty smell.
This air conditioner smell is likely caused by a dirty evaporator coil or clogged condensate drain. If it's the former, you can help by spraying your condenser with a hose to clear out dirt and debris (turn off the disconnect first). But you should consider a A/C tune up for a professional clean.
Every time your AC comes on, the air leaving your vents stinks with a musty odor. What in the world could it be? Most likely it's the smell of mold and/or mildew. That's bad news because your AC is most likely distributing mold and/or mildew spores throughout your home.
If you smell sewage when you turn on your A/C unit, your sewer system may have backed up into your house or near your unit, and the smell may come from a ruptured pipe. Contact an air conditioning company right away if you notice a sewage smell or detect methane in your home. Do not let this problem linger!
When you turn on the AC unit again for the first time in a while, it will likely smell like burning. The good news is that this smell should disappear within just a few minutes. However, if you do find that the smell persists for longer, then it's time to get in touch with our team as there may be a more serious issue.
Generally, a well-maintained air conditioning unit won't make you sick. However, your AC can potentially increase your chance of getting sick if it circulates cold-causing viruses. If mould, bacteria, or other microbes grow in your unit, you may experience several irritating symptoms.
A dirty AC system can lead to many breathing problems. If you have a runny or stuffy nose that develops when you're inside but goes away when you leave, this is a clear indication that your air conditioner's filter is dirty.
Exhaust Fumes
If your AC smells like an exhaust pipe, then you could have a refrigerant leak. These leaks can not only be dangerous to your health, but they can also shorten your HVAC system's lifespan.
If you notice your air conditioner smells bad like dirty socks when turned on, you can check the evaporator coil for mold growth by removing the access panel on the indoor unit's cabinet and take a peek. If you see mold, call your HVAC technician to fix the problem by cleaning the coils with appropriate cleaners.
An air conditioner that smells like rotten eggs or sulphur almost always means one thing: there's a gas leak in your house, which is getting into your ductwork. Natural gas is a hazardous substance. It can catch fire, explode, and/or reduce oxygen levels in the bloodstream with severe, often fatal, consequences.
Clean Your AC Drain Line With Vinegar
You can start by pouring 1/4 cup of vinegar through a funnel into the drain; slowly add more if needed. Let the vinegar sit for a few hours to eat away any algae buildup before flushing the pipe out with water.
Flush Condensate Drain Line
The repair cost to have the drain line flushed runs between $75 to $250. If replacement is needed because the condensate drain line is damaged, a new condensate drain line is usually only around $20.
Regularly cleaning is the best way to prevent clogging in the air conditioner drain line outside the house. Cleaning at least once a year is usually the rule of thumb, but if you live in Arizona where air conditioning is used often, you may need to do it more frequently.
Birds and rodents can take shelter in your air duct during the winter, where they often die and begin to decompose. That's why, when you turn on your AC, a horrible odor circulates throughout your home. Your ducts will need to be professionally cleaned to get rid of any animal remains and remove the smell.
If your home has a stale, musty scent, there could be a handful of explanations, including a plumbing leak, high humidity, poor airflow, dirty HVAC equipment, or soiled carpet.