When you switch on your aircon after weeks or months of not using it, you may notice a musty or dirty smell. This is very common in Singapore’s humid weather. The smell usually comes from mould, dirt, or trapped moisture inside the unit. However, the good news is that the problem is easy to fix. You can also prevent it from coming back with simple cleaning habits and regular aircon servicing in Singapore.
Why Your Aircon Smells Dirty After Being Idle
1. Moisture Trapped Inside the Unit
When your aircon stays idle, moisture does not dry out. It sits inside the coil and drain tray. As a result, bacteria and mould begin to grow quickly. This happens often in Singapore’s humidity, which speeds up mould growth even more.
2. Dust and Dirt Build-Up
Dust settles on the blower, coil, and filters when the unit is turned off. Eventually, this dust mixes with moisture and creates a stale smell. When you turn the aircon on, the smell spreads through the room. This problem affects many HDB and condo aircon units in Singapore.
3. Mouldy Filters
Dirty filters trap moisture. Soon, mould begins to grow on the surface. When air passes through them, it carries the smell everywhere. Moreover, this is one of the most common issues found during aircon servicing in Singapore.
4. Clogged Drain Pipe
A clogged drain pipe holds water inside the system. Over time, the trapped water begins to smell. This issue is especially common in older HDB aircon systems that haven’t been cleaned for months.
5. Dirty Blower Wheel
A blower full of dust and grease produces a strong dirty smell. Additionally, it reduces airflow and weakens cooling. In many cases, the blower needs a professional chemical wash to clean it completely.
Best Ways to Clean and Remove the Dirty Smell
1. Clean or Replace Air Filters
Remove the filters and wash them with mild soap. Rinse them well. After that, allow them to dry fully before placing them back. If the smell continues, the filters may need replacement. This is common in Singapore HDB flats and condos.
2. Vacuum the Blower Area
A vacuum can remove loose dirt and dust. However, if the dirt is thick or sticky, you will need a professional aircon cleaning service to clean it properly.
3. Clean the Evaporator Coil
You can use a coil spray to clean light dirt. But, if the coil has mould or heavy dirt, only a chemical wash in Singapore can clean it well. This deep cleaning removes odour-causing buildup.
4. Flush the Drain Pipe
A blocked drain pipe needs a full flush. This removes slime, mould, and stale water. Otherwise, the bad smell will return after a few days. This issue becomes worse during Singapore’s rainy season.
5. Get a Chemical Wash
If your aircon has been idle for many months, a chemical wash or chemical overhaul is usually the best solution. It cleans the coil, blower, drain tray, and drain pipe thoroughly. Moreover, it removes hidden mould that regular cleaning cannot reach. Consequently, your aircon smells cleaner and cools better.
How to Stop the Smell From Returning
1. Run Your Aircon Weekly
Turn your aircon on for 10–15 minutes each week. This way, moisture does not stay trapped inside. It is one of the simplest habits for Singapore homeowners.
2. Clean Filters Every 2–4 Weeks
Regular filter cleaning prevents dust and odours from building up. Additionally, clean filters improve airflow and cooling.
3. Use Dry Mode
Dry mode helps remove moisture from the unit before you switch it off. Therefore, it slows down mould growth in both HDB and condo aircon units.
4. Schedule Regular Servicing
Professional servicing every 3–4 months keeps your aircon clean inside and out. Furthermore, it prevents mould from forming in hidden areas. Many aircon servicing companies in Singapore recommend this servicing schedule.
When You Should Call a Professional
If the dirty smell stays even after you clean your filters, you may need deeper cleaning. Hidden mould in the blower, coil, or drainage system can create stubborn odours. In this case, a technician should inspect the unit. This ensures the smell is removed and does not return.
Book Your Aircon Cleaning With Lion City Aircon
If your aircon smells dirty after being idle, we can clean it quickly, safely, and thoroughly.
📞 Book your service now: +65 8818 5781
🌐 Visit us: lioncityaircon.sg
✔ Professional aircon servicing in Singapore
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Stay fresh, breathe cleaner air, and enjoy a healthier home.
