Calculator Inputs
Example Data Table
| Scenario | Method | Input Power | Hours/Day | Rate | Estimated Monthly kWh | Estimated Monthly Cost |
|---|---|---|---|---|---|---|
| Bedroom split unit | Direct Rated Power | 1200 W | 7 | 0.16 | 195.30 | 31.25 |
| Office wall unit | BTU + EER | 18000 BTU/h, EER 10 | 9 | 0.18 | 374.76 | 67.46 |
| Retail cooling zone | kW + COP | 5.27 kW, COP 3.2 | 10 | 0.15 | 387.66 | 58.15 |
| Efficient inverter unit | BTU + SEER | 12000 BTU/h, SEER 18 | 8 | 0.14 | 129.92 | 18.19 |
Formula Used
Input Power (W) = Rated Watts
Input Power (W) = Cooling Capacity (BTU/h) ÷ EER
Input Power (W) = Cooling Capacity (kW) × 1000 ÷ COP
Average Input Power (W) ≈ Cooling Capacity (BTU/h) ÷ SEER
Daily Operating kWh = Effective Input Power (kW) × Hours per Day × Number of Units
Effective Input Power (W) = Rated Input Power × Load Factor
Daily Standby kWh = Standby Power (kW) × Non-operating Hours × Number of Units
Energy Cost = Energy Use × Tariff
Estimated Current (A) = Power (W) ÷ [Voltage × Power Factor]
This calculator assumes single-phase current estimation and a stable tariff. Real bills can vary because of thermostat cycling, weather, insulation, compressor control, and billing slabs.
How to Use This Calculator
- Select the method that matches your equipment data.
- Enter either rated watts, BTU with EER, kW with COP, or BTU with SEER.
- Add average load factor to reflect real operating behavior.
- Enter daily operating hours and monthly operating days.
- Enter electricity tariff, standby watts, and the number of units.
- Add demand charge, fixed charge, voltage, and power factor when needed.
- Press Calculate Consumption to show results above the form.
- Review the summary cards, Plotly chart, and download options.
Frequently Asked Questions
1. What does load factor mean here?
Load factor reflects average compressor demand compared with full rated power. Air conditioners rarely draw full input continuously. A lower factor often better matches cycling or inverter operation.
2. Which method should I choose?
Choose direct power when your nameplate lists watts. Use BTU and EER when those ratings are available. Use kW and COP for engineering specifications. Use BTU and SEER for seasonal efficiency estimates.
3. Why include standby watts?
Many systems consume small standby power for controls, Wi-Fi, or crankcase heating. This value is usually small, but it can matter across many units or long idle periods.
4. Does this calculator include demand charges?
Yes. Enter a demand charge rate if your bill includes a kW-based fee. The tool multiplies peak running demand by that rate and adds it to the monthly bill estimate.
5. Is the current calculation exact?
No. It is an engineering estimate for single-phase operation using voltage and power factor. Starting current, multi-phase supply, and variable-speed drives can change the real measured current.
6. Can I use this for inverter air conditioners?
Yes. Inverter units often run below full rated demand. Enter a realistic load factor to approximate average behavior, or use an average measured wattage with the direct power method.
7. Why might my real bill differ?
Real electricity bills depend on weather, thermostat settings, maintenance condition, duct leakage, insulation, tariff slabs, and varying daily usage. This tool gives a structured estimate, not a utility invoice.
8. What is the best input source for accuracy?
Measured wattage from a meter is usually the strongest input. Nameplate watts are also useful. Efficiency-based methods are excellent for early estimates when direct electrical measurements are unavailable.