How to calculate air conditioner power consumption
Basic Formulas
Power consumption (kWh) = Power (kW) × Actual compressor operating time (h)
1 unit of electricity = 1 kilowatt-hour, 1000W = 1 kW
Important: Do not calculate based on how long the machine is turned on! Fixed frequency machines will shut down when they reach the set temperature; variable frequency machines will reduce the frequency and power consumption.
I. Check the nameplate for the [cooling input power] (most accurate).
Nameplate/Energy Efficiency Label: Cooling Input Power (W)
Example: Input power 1000W
The electricity consumption for continuous operation at full load for 1 hour is: 1000 ÷ 1000 × 1 = 1 kWh
Fixed-frequency air conditioners : The compressor is either fully on or off.
Estimation: Full power × On-load rate (typically 0.5~0.8)
Example: 1.5 HP fixed-frequency air conditioner, cooling input 1100W, average room insulation, load factor 0.7.
Hourly electricity consumption = 1.1kW × 0.7 = 0.77 kWh
Inverter air conditioners : power changes dynamically, with high power when first turned on and low frequency and low power after the temperature stabilizes.
The nameplate indicates the maximum input power , which cannot be directly used to calculate normal power consumption.
You can check the energy efficiency label for the "cooling season power consumption": the national standard is based on the average value calculated over a 1136-hour cooling season.
Average hourly power consumption ≈ seasonal power consumption ÷ 1136
Example: Electricity consumption during the cooling season is 600 kWh → 600 ÷ 1136 ≈ 0.53 kWh/hour (average)
II. an additional electric auxiliary heater must be added for heating.
Heating power consumption = Heating input power + Electric auxiliary heating power
For example: heating input is 1200W, electric auxiliary heating is 800W, and full power is 2000W, consuming 2 kWh per hour. This amount is not needed if the electric auxiliary heating is not used.
III. Use cooling capacity and energy efficiency ratio to estimate (when there is no nameplate).
Input power (W) = Rated cooling capacity (W) ÷ EER (fixed frequency) / APF (inverter frequency)
Example: Cooling capacity 3500W, APF=5
Input power ≈ 3500 ÷ 5 = 700W = 0.7kW
Rough estimate of horsepower (estimate only, refer to the nameplate first).
1 horsepower (2500W cooling): Approximately 700~850W at full load.
1.5 HP (3500W cooling): Approximately 1000~1300W at full load.
2 HP (5000W cooling): Approximately 1600~2000W at full load.
IV. Key Factors Affecting Power Consumption
Setting the temperature to 26℃ saves a lot of electricity compared to 22℃.
Room insulation, western exposure, ceiling height, and door/window operation.
Outdoor temperature, whether the door is opened frequently
Fan speed, sleep mode, ECO energy-saving mode
Example of complete calculation
A 1.5 HP inverter unit, nameplate: maximum cooling input 1200W, seasonal power consumption 650kWh.
Run for 8 hours, the room is well insulated, then stabilize and run at low frequency:
Average hourly output: ≈650 ÷ 1136 ≈ 0.57 degrees Celsius
Electricity consumption in 8 hours ≈ 0.57 × 8 = 4.56 kWh
