What Is Causing Your Air Conditioner To Smell Bad

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Have you started to notice a foul smell around your home, especially when your AC is running? It makes sense that you want to find where the smell is coming from, but you might not realize that these bad smells can also cause a serious health hazard. Below are some of the common causes as to why your air conditioner smells bad.

1. Mildew, Mold, And Must

If you have excess moisture of humidity inside your HVAC system, mildew or mould may be present in the ductwork. To prevent moisture or mildew problems, water leaks must be fixed, drainage improved, replace your aircon filters frequently, and schedule aircon servicing every 6 months.

If earth or soil is exposed in your basement or crawlspace, it may be worthwhile finding a way to cover up the soil. One of the easiest ways to safeguard your valuables and to stop mildew and mould from growing in your HVAC system and your home is to invest in a whole-house dehumidifier. This device directly connects to your HVAC system where it works on automatically removing the right levels of moisture present in the air. The condensate is then deposited outdoors. These devices are effective at removing humidity and moisture as soon as it enters your home.

When you book your next air-conditioning tune-up, ensure that the company you decide to hire offers a comprehensive cleaning service. These inspections include clearing out the condensate drain-line, detecting any mildew or mould problems, and cleaning the evaporator coils.

2. Stinky Feet Or Dirty Socks Smells

Stagnant water, condensate drain-pans that are clogged, or dirty and grimy evaporator coils can result in the smell of stinky feet or dirty socks. The solution to this problem involves a professional clean.

3. Burning Smell

If anything gives off a burning smell, then it most probably is burning. When it comes to AC systems, this is caused by wiring issues, overheating motors, or other types of mechanical issues. If you ever smell a burning odour, turn your HVAC unit off at your breaker box immediately.

In some cases, you may smell something that smells like gun powder. This is an indication of a short in either the fan motor or the AC’s circuit board. If the burning smell continues, leave your home immediately and call the local fire department. Plastic components that start melting in your AC system also emit a rotten egg or fishy smell. Turn the unit off at your breaker box, and call an AC technician immediately. If you are concerned about a fire starting, call the local fire department.

4. Sewage Smell

Sewer gases will back-up into your home when the P-traps are dry. You should be running water down all the sinks in your home, at least every month. This will keep the P-trap filled, which creates a seal, preventing sewage odours. If a dry P-trap is not the problem, the sewer vent pipes may have ruptured or the sewer line may be backed up. Sewer gases are often hazardous, which is why you should contact a professional HVAC technician or plumber right away.

5. Dirty Trash Or Rotting Carcass Smell

If something like a mouse, bird, or rat has died inside a duct system or your HVAC, you will soon notice a very bad odour. As soon as you notice this type of smell, turn your AC system off. Open windows and doors for ventilation, and call a pest control company or an HVAC technician as soon as you can.

6. Rotten Egg Or Sulfur Smell

It is important not to ignore the odour of sulfur or rotten eggs. This could be an indication of a gas leak. Even though natural gas doesn’t smell like anything, there is a chemical known as mercaptan added to the gas that emits a distinctive “rotten-egg” gas smell. If you do notice the smell of rotten eggs or sulfur coming out of your AC vents, please follow these steps:

  • Do not operate a lighter or matches
  • Do not operate or use any electrical device
  • If you have an open flame such as a candle burning, put it out immediately
  • Open all the windows and doors in your home
  • Turn the gas supply off. If you are unable to shut the gas off, contact your gas company and ask them to come out and shut it off
  • Leave your home

Avoid turning the gas on again. Rather contact a gas company, to reconnect your gas

Solutions For Indoor Air Quality

The EPA in the US has indicated that poor air quality indoors, is among the top health threats across the US. Dirt, dander, microbes, fungus, pollen, hair, and dust accumulate inside the air ducts and your HVAC equipment, and most cause a lot of health problems. At the same time, these pollutants are also responsible for damaging the internal parts in an HVAC system, which leads to far more frequent breakdowns and repairs.

Why Its A Bad Idea To Cover Up Smells

If you use scented candles, aerosol sprays, and air-fresheners to try and mask or hide smells coming from your HVAC system, this will only worsen the overall air quality in your home. To save yourself and your family from irritated skin and eyes, breathing problems, nausea, headaches, along with a host of other health issues. Schedule an air-quality inspection from a professional company.

How do I eliminate the smell in my air conditioning system?

Here are 4 simple steps to fix an issue most people find when they have smelly air conditioning.

1. Turn Off the AC power

When dealing with an electrical system, the first thing to turn off power at the source. This prevents injury from a faulty AC system and ensures safety for everyone.

2. Change or Clean the air filter

Cleaning or changing the air filter is an essential step in the process to eliminate a funny smell. It’s also one of the most straightforward steps if you know where it is.

When you change your filter, look for mould on it. If there is any mould on your AC system, be sure to clean it off with bleach and water.

Your AC drain pipes should be clean, clear of debris, and appropriately sized for your system. Check them once a month to make sure you are not having issues.

3. Cleaning the AC evaporator coils

If the smell persists after you have changed or cleaned your filter, then there is a good chance that it could be coming from the evaporator coils inside your air conditioner.

When you have finished cleaning or changing the filters, use a foaming coil cleaner agent to clean the evaporator coils. The coils tend to get dirty during their regular operation, and it causes the AC system efficiency to reduce.

4. Cleaning the AC condensate line

The condensate line is another area that tends to get dirty as a result of the AC system working. It’s important to clean it out periodically so that you prevent the formation of mould in your home. Be sure to keep the ventilation grill around the condensate pan in good condition, and make sure there isn’t any trash or debris in or around the ventilation.

The Bottom Line

Bad odours or smells coming from an AC system is unpleasant, and it can become a threat to the health of your family. Depending on the smell and the source, these problems can lead to allergies, asthma attacks, skin irritation, respiratory issues such as infections and cough, sore throats, dizziness, painful and red eyes, and more.

Bad odours are often an indication that your air-conditioner is experiencing a malfunction, which usually requires an expert and professional check-up. Some of the things that you can do to maintain your AC system, is to check on the filters according to the recommendation provided by the manufacturer.

Related read: 9 Most Popular Air Conditioner Problems & How To Deal With Them



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