The single most common mistake people make with inverter aircons is applying the rules from the old non-inverter era. The technology is different. The right behaviour is different.
A non-inverter aircon runs its compressor at one fixed speed. It is either fully on or fully off. When a room gets too warm, the compressor kicks back on at full power; when it reaches the target, it cuts out completely. This simple on/off cycling is why older units sound distinctly louder and quieter in cycles.
An inverter aircon adjusts compressor speed continuously. When first cooling a warm room it runs at high speed; once near the target temperature it slows down significantly, running at maybe 20–30% of full capacity to maintain comfort. This variable-speed operation is what makes it efficient — but it also means the unit consumes the most power during the ramp-up phase when it restarts after being off.
| Feature | Non-Inverter | Inverter |
|---|---|---|
| Compressor | Fixed speed (on/off) | Variable speed |
| Startup power draw | High, but brief | High and prolonged |
| Steady-state efficiency | Lower | 30–50% better |
| Best used | Short, intermittent cooling | Sustained cooling periods |
| Turn off when leaving? | Yes, almost always | Only if gone 4+ hours |
With an inverter unit, every time you turn it off and back on, it has to ramp up from zero — consuming peak power for the first 10–20 minutes while cooling the room back down. That startup cost can exceed what you would have spent simply keeping the unit idling at a raised setpoint. Teko.ph's HVAC specialists, who service units across the Philippines, put the crossover point at roughly four hours: for absences shorter than that, raise the temperature rather than turning it off; for longer absences, turn it off.
The old rule still applies: turn it off when you leave. Non-inverter units do not have the same startup efficiency penalty, and their on/off cycling behaviour means there's no sustained idle-efficiency benefit to staying on. Most residential units installed before about 2015 in tropical Asia are non-inverter; newer installations are almost exclusively inverter.
Check the outdoor unit's label or your original documentation — the word "Inverter" is typically prominent in the model name or on the energy efficiency label. If you are unsure, listen: a non-inverter unit cycles audibly on and off during normal operation, while an inverter unit hums continuously at varying intensity without clear cut-off points.
Our calculator assumes a current-generation inverter unit for all its estimates. If you have a non-inverter unit, your actual consumption is typically 20–50% higher than shown.