Aircon Smells Bad When Turned On? Here’s How to Fix It

Is your air conditioner releasing unpleasant odours when you turn it on? You’re not alone. Many homeowners face this issue, especially during warmer months when the aircon runs frequently.

A smelly air conditioner can quickly turn your cool oasis into a less-than-refreshing environment. But what’s causing that bad smell? It could be anything from mould and mildew to dust, or even a hidden leak.

The good news is that these odours often have simple solutions. By understanding the possible causes, you can tackle the problem and keep your heating, ventilation and air conditioning (HVAC) system smelling fresh.

In this guide, we’ll explore common reasons for aircon odours and walk you through practical steps to fix them, so you can get back to enjoying clean, cool air at home.

Causes of Bad Smells from Your AC

If your air conditioner releases a foul odour, it’s likely due to one of these common causes:

• Mould and mildew: Moisture build up inside your air conditioner can create the ideal environment for mould and mildew to grow, leading to a musty or sour smell. This often happens when the unit isn’t draining properly.
• Dirty filters: Over time, filters trap dust, dirt, and debris. If left unchecked, this build up can create a stale smell every time you turn on your aircon. Dirty filters also reduce air quality and put strain on the unit.
• Clogged drain lines: When the drain line is blocked, water can accumulate and start to smell bad. In some cases, this standing water may even leak, causing further issues.
• Pests or dead animals: Small animals or insects can sometimes find their way into the system. If they get trapped and die inside, they’ll quickly start to smell, which can be quite unpleasant.
• Refrigerant leaks: If the smell is chemical-like or sweet, it could indicate a refrigerant leak. This is a more serious issue and should be addressed by a professional right away.

Understanding these causes can help you pinpoint the problem and take steps to eliminate the odour.

How to Identify the Source of the Odour

When your air conditioner starts to smell, the first step is to identify the source of the odour. Different smells can indicate different issues, so pay attention to the scent. A musty odour often points to mould or mildew, which can build up if moisture accumulates inside your unit.

You might notice a sour smell if the drain pan is clogged or there’s stagnant water in the system. A burning smell could be a sign of electrical issues, which are best handled by a professional.

Start by checking the air filters and coils. Dust and debris can trap moisture, creating the perfect environment for mould to grow. If you spot visible mould or mildew, clean it up right away.

Next, inspect the drain line and drain pan for any standing water, which could be causing the odour. You should also look for any dead pests or other obstructions in the unit, as these can cause foul smells.

By identifying the source of the odour, you can take the right steps to fix it and restore fresh, clean air.

DIY Fixes for Aircon Odours

If your aircon is releasing unpleasant smells, here are some DIY solutions to freshen things up:

• Clean the air filters: Dirty filters are a common cause of bad odours. Remove the filters and give them a good wash with mild soap and water. If they’re too clogged or damaged, it’s time to replace them. Clean filters also improve air quality and efficiency.
• Clear the drain line: A clogged drain line can cause musty smells. Use a wet/dry vacuum or a pipe cleaner to clear any debris. Flush it out with a bit of vinegar to kill mould and mildew and prevent future clogs.
• Wipe down coils and interior parts: Dust and moisture can build up on coils, creating an ideal environment for odours. Use a soft brush or cloth to gently clean the coils and any accessible interior parts.
• Use odour neutralisers: For a quick fix, try using natural odour neutralizers, like baking soda, or commercial air fresheners. Be cautious with sprays that contain chemicals, as they may affect your air conditioner’s components.

By following these steps, you can often eliminate unpleasant aircon smells and enjoy fresh, cool air again.

When to Call a Professional

While some aircon smells can be handled with DIY fixes, there are times when it’s best to bring in a professional.

Here’s when to consider calling an expert:

• Persistent odours: If you’ve tried cleaning the filters, coils, and drain line, but the smell won’t go away, it may indicate a deeper issue, such as hidden mould or mildew, which needs professional cleaning.
• Chemical or sweet smells: A strong, chemical-like odour could indicate a refrigerant leak. Since refrigerant is hazardous and requires proper handling, it’s essential to get a licensed technician to inspect and repair the leak.
• Electrical or burning smells: If you detect any smell of burning or melting plastic, turn off your aircon immediately and call a professional. This could signal an electrical issue or overheating components, which can pose a fire risk.
• Suspected dead animals: If you suspect that a pest has found its way into your air conditioner, a professional can safely remove it and perform a thorough cleaning to get rid of any lingering odours.

Calling a qualified HVAC technician ensures that your aircon is safe, functional, and odour-free.

Breathe Fresh Air Again

A smelly air conditioner can be a nuisance, but it’s often a fixable problem. By understanding the common causes − like dirty filters, mould or clogged drain lines − you can tackle many odours on your own.

Regular maintenance, such as cleaning filters and checking for moisture build up, can help prevent bad smells from reoccurring.

However, if you’re dealing with persistent or unusual odours, like a chemical smell or something that resembles burning, it’s best to call a professional. They can diagnose and repair issues safely, ensuring your air conditioner is running smoothly.

With a little attention and care, you can keep your aircon fresh and enjoy clean, cool air in your home. So, don’t let bad smells linger − take action and restore your aircon’s refreshing comfort.

Please note: This information is provided for advice purposes only. Regulations differ from state to state, so please consult your local authorities or an industry professional before proceeding with any work. See our Terms & Conditions here.