Why your aircon bill jumps in March (and what to do)
Every March our WhatsApp lights up with the same message: “TNB bill RM 80 higher this month, what's wrong with the aircon?” The answer is almost never something dramatic. Three small things stack up at this time of year.
One: the dry season starts
February and March are typically Malaysia's driest months. With less rain washing dust out of the air, your outdoor condenser coil gets dirty faster. A 5% reduction in air-flow through the condenser pushes the compressor about 8% harder.
Two: the indoor coil has now been running for nine to twelve months
If you had your last chemical overhaul in May or June of the previous year, the indoor coil has accumulated nine to twelve months of biofilm. The compressor has to work longer cycles to hit the same set temperature. The energy meter doesn't mind — but you do.
Three: hot afternoons mean the unit cycles less often
In the hot months the aircon doesn't get the cool-down break a wet afternoon usually gives it. A compressor that runs for two solid hours uses more energy than one that runs for ninety minutes spread across the afternoon.
What to do, in order of cost
- Set the thermostat 1°C higher. Sounds trite but it's the single largest lever you have — roughly 6% saving per degree.
- Clean the filters yourself. Pop them out, rinse with cold water, leave to dry. Twenty minutes. Restores most of the air-flow loss.
- Book a basic service. RM 80–130 per unit. Buys you another three months.
- Book the chemical overhaul. If the basic service doesn't bring things back to normal, the indoor coil and blower need the full treatment.
When something is genuinely wrong
If your bill has jumped 30% or more compared to the same month last year, that's outside seasonal variation and worth checking. The most common culprits are a refrigerant leak (the unit runs longer because it can't hit temperature), a stuck reversing valve on an inverter unit, or a tired capacitor causing the compressor to run hot. Tell us the model and we'll diagnose it.