Chennai's northeast monsoon (October–December) and the southwest monsoon (June–September) bring rain, high humidity, and frequent power cuts — all of which affect how your AC works and how it should be maintained. These 6 steps will protect your AC and keep it running efficiently through the wet season.
1. Don't Switch Off the AC Completely During Monsoon
Many people assume they don't need the AC during monsoon because it's cooler. This is partly true — but running the AC in dehumidifier mode for 1–2 hours a day during heavy rain periods is very beneficial.
Chennai's monsoon humidity often exceeds 85–90%. This high humidity makes rooms feel sticky and uncomfortable, and encourages mould growth on walls, fabrics, and — inside your AC unit. Running the AC removes moisture from the air, keeping the room drier and preventing mould inside the unit.
Most modern ACs have a Dry mode (look for a water droplet symbol on the remote). This mode runs the fan at low speed and cycles the compressor briefly — removing humidity without over-cooling. Use it on rainy days when you want dryness without the cold.
2. Protect the Outdoor Unit from Direct Rain
Outdoor units are designed to withstand rain — they're weatherproof. However, problems arise when:
- The unit is positioned where rainwater accumulates and submerges the base
- Leaves and debris blown by monsoon winds block the fins
- Heavy rain hits the unit horizontally (common in upper-floor installations)
Ensure the outdoor unit is elevated on its bracket and has drainage below. Clear any leaf or debris accumulation from the fins after heavy rain — do this with the unit switched off and power disconnected.
3. Check and Clean the Drain Pipe More Frequently
During monsoon, humidity is high and the AC removes more water from the air than usual. The condensate drain pipe handles significantly more water. If there's even a partial blockage, it overflows — causing water to drip from the indoor unit.
Check the drain pipe outlet (usually a pipe exiting through the wall) every 2 weeks during monsoon. If water isn't dripping from it during AC operation, the pipe may be blocked. Flush it with water or call for a service.
4. Use a Voltage Stabiliser During Monsoon
Power cuts and voltage fluctuations are frequent during Chennai's monsoon. When power returns after a cut, voltage often surges before stabilising — this can damage the AC compressor or blow capacitors.
If you don't have a voltage stabiliser, follow the 3–5 minute wait rule: do not switch the AC on immediately when power returns. Wait until fans and lights have been running stably for a few minutes.
5. Service Your AC Before Monsoon Peak (September)
The best time to service your AC in Chennai is just before the monsoon peaks in October. A pre-monsoon service:
- Cleans the coils of summer dust buildup
- Flushes the drain pipe so it can handle extra water
- Checks the electrical connections that may have loosened in summer heat
- Verifies gas level — running with low gas in high humidity further reduces efficiency
6. Watch for Mould and Musty Smells
Monsoon is the peak season for mould growth inside AC units. If your AC starts smelling musty after rain, it's mould on the evaporator coils or inside the drain tray.
Prevention: Run the AC in fan-only mode for 20–30 minutes before switching it off each day. This dries the coils and dramatically reduces mould growth. Many new ACs have an auto-clean function that does this automatically — use it if your AC has it.
What to Do If the AC Was Flooded During Heavy Rain
If floodwater entered your home and reached the indoor or outdoor unit, do not switch the AC on. Water inside electrical components causes short circuits. Call a technician to inspect and dry out the unit before restarting — this applies even if the water level was low.
RK Aircon provides monsoon AC servicing across Chennai. A pre-monsoon service costs ₹400–800 and prevents the most common monsoon-season breakdowns.