6 Common HVAC Smells And How To Fix Them?

6 most common air conditioner smells and the best way to resolve them Expert tips and solutions to eliminate unpleasant odors in your home.

Updated on Jul 26, 2023
5 min read
6 Common HVAC Smells And How To Fix Them?

An air conditioner should not emanate any smells or odors. In fact, you should not smell anything odd if your AC is running properly and is clean. Weird smells and unusual air conditioner noises are indicative of something wrong in your Bay Area home or business. If your AC is aging and you haven’t had it maintained in a while, smells could be a clear sign that you require an AC tune-up.

These are 6 most common air conditioner smells and the best way to resolve them:

1. Chemical Smell

Chemical smell from an air conditioner is never a good sign. It could be a sickly sweet smell, which indicates a refrigerant leak. Copper coils can crack over time causing the gas to leak. These are a few other clues that you are probably dealing with a refrigerant leak:

  • Hissing or bubbling sound when an AC comes on
  • Frost on the evaporator coil or refrigerant lines
  • Increasing energy expenses
  • Difficult to keep your house comfortable or at a set temperature

Refrigerant leaks require professionals. Your cooling technician will fix the leak and recharge the system with refrigerant.

2. Rotten Egg Odor

An air conditioner that smells like rotten eggs could indicate a natural gas leak. Natural gas has a chemical added to it to make it smell like sulfur or rotten eggs. You should not take this lightly. These are a few steps to take if you detect a rotten egg odor:

  • Opening windows
  • Shutting off the gas supply
  • Calling the gas company
  • Going outside immediately

3. Musty Smell

Homeowners that have a musty smell in their house frequently compare it to dirty socks, feet, or an ill-maintained locker room. This musty smell can be attributed to a filthy evaporator coil with bacteria, mold, and mildew buildup. Moisture can also make the AC smell bad. This type of odor is usually common in areas where heating is used at night and cooling is set for during the day.

The best way of getting rid of a musty smell is to have your AC maintained regularly. You should also keep the air filters clean by replacing them.

4. Vinegar Like Smell

Mildew or a pungent vinegar like smell could be prompted by several concerns, such as:

  • Extra condensation
  • Filthy filter
  • Moldy ductwork or AC
  • Blocked drain line or condensate pan

You should have the filter checked and if you haven’t had it cleaned within 3 months, you should change it. Don’t hesitate in calling professional contractors if this doesn’t get rid of the smell.

5. Burning Plastic Odor

There may be several things wrong with an air conditioner that has a burning smell or a fishy odor. These are:

  • Motor needs lubrication
  • Overheating motor because of a broken capacitator
  • Electrical issue
  • Broken fan belt

You should immediately have electrical malfunctions examined to avoid a fire. Switch off the AC if you notice any burning plastic. You should immediately call an expert AC service tech to fix the issue.

6. Cat Pee Smell

Mold is usually the culprit in case of an overpowering ammonia odor. This could be within the ductwork or the AC. The smell doesn’t come from the mold, but from the mycotoxins produced by mold. These compounds are toxic to health and wellness. You should not delay in speaking with a professional AC maintenance contractor. They may need to clean the ductwork and service the AC to get rid of the cat pee smell.

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