Air Conditioner Electricity Cost & Power Consumption Calculator 2026
Air conditioners account for over 55% of an Indian household's summer electricity bill. Calculating power costs requires more than checking the wattage printed on the box, because inverter compressors alter motor speed dynamically. Once a room reaches the set temperature, an inverter unit throttles down, drawing far less electricity than its rated maximum. The Bureau of Energy Efficiency (BEE) rates cooling appliances through the Indian Seasonal Energy Efficiency Ratio (ISEER). A 5-star inverter unit delivers an ISEER of 5.0 or above, yielding 5 units of cooling per unit of electrical input. If your room sits beneath an exposed terrace or receives afternoon western sun, radiant heat forces the compressor to run longer at higher wattage, adding 20% to 35% to monthly power consumption.
Compared to continuous 18°C freezing operation, you save approximately () every month!
How to Use the AC Electricity Cost Calculator
Select AC tonnage for room size
Pick 1.0 Ton for rooms under 120 sq ft, 1.5 Ton for bedrooms between 130 and 180 sq ft, or 2.0 Ton for living rooms over 200 sq ft.
Choose star rating and compressor type
Select 3-star or 5-star inverter or fixed-speed compressor to match your unit's certified BEE ISEER efficiency.
Enter daily runtime and thermostat setting
Enter typical daily hours and setpoint. Setting 24°C rather than 18°C lowers compressor workload and cuts consumption by roughly 35%.
Input state electricity board slab rate
Enter your DISCOM per-unit rate (typically ₹6.00 to ₹8.50 per unit for middle domestic slabs) to calculate daily, monthly, and seasonal power costs.
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Understanding AC Power Draw and the ISEER Formula
An air conditioner's rated cooling capacity in British Thermal Units (BTU) or Tons does not equal its electrical wattage draw. 1 Ton of cooling equals 3,516 Watts (12,000 BTU/hr) of heat removal, not electricity consumed. The electrical power drawn depends on the Indian Seasonal Energy Efficiency Ratio (ISEER).
Power Input (Watts) = Cooling Capacity (Watts) ÷ ISEER Rating
Daily Units (kWh) = (Power Input in Watts × Runtime Hours × Duty Cycle Factor) ÷ 1,000
Monthly Cost (₹) = Daily Units × 30 Days × Electricity Board Slab Rate (₹/kWh)
BEE Star Rating and Power Draw Benchmarks (1.0 to 2.0 Ton)
Based on 8 hours nightly operation at 24°C in standard 150 sq ft insulated bedrooms at ₹7.00 per unit.
| Capacity | Star & Type | ISEER | Avg Draw (24°C) | Daily Units | Monthly Units | Monthly Bill |
|---|---|---|---|---|---|---|
| 1.0 Ton | 5-Star Inverter | 5.20 | 590 W | 4.72 kWh | 142 Units | ₹994 |
| 1.0 Ton | 3-Star Inverter | 3.90 | 750 W | 6.00 kWh | 180 Units | ₹1,260 |
| 1.5 Ton | 5-Star Inverter | 5.20 | 850 W | 6.80 kWh | 204 Units | ₹1,428 |
| 1.5 Ton | 3-Star Inverter | 3.90 | 1,020 W | 8.16 kWh | 245 Units | ₹1,715 |
| 1.5 Ton | 3-Star Non-Inverter | 3.60 | 1,350 W | 10.80 kWh | 324 Units | ₹2,268 |
| 2.0 Ton | 5-Star Inverter | 5.00 | 1,130 W | 9.04 kWh | 271 Units | ₹1,897 |
| 2.0 Ton | 3-Star Inverter | 3.90 | 1,500 W | 12.00 kWh | 360 Units | ₹2,520 |
Real-World Calculation Case Studies
1.5 Ton 5-Star Inverter at 24°C (8 Hours Overnight)
• Rated Watts: 5250 ÷ 5.2 = 1,010 W
• Effective Draw at 24°C: 850 Watts (0.85 kW)
• Daily Units: 0.85 × 8 hrs = 6.80 kWh
• Monthly Units (30 days): 204 Units
• Monthly Bill @ ₹7.00/unit: ₹1,428.00
1.5 Ton 5-Star Inverter at 18°C (8 Hours Overnight)
• Compressor runs near peak load: ~1.31 kW continuous
• Daily Units: 1.31 × 8 hrs = 10.50 kWh
• Monthly Units (30 days): 315 Units
• Monthly Bill @ ₹7.00/unit: ₹2,205.00
• Extra Wastage vs 24°C: +₹777 / month (111 units wasted)
1.0 Ton 3-Star Inverter at 24°C (10 Hours Usage)
• Effective Draw at 24°C: 750 Watts (0.75 kW)
• Daily Units: 0.75 × 10 hrs = 7.50 kWh
• Monthly Units (30 days): 225 Units
• Monthly Bill @ ₹6.50/unit: ₹1,462.50
2.0 Ton 5-Star Inverter at 24°C (6 Hours Daytime)
• Effective Draw at 24°C: 1,130 Watts (1.13 kW)
• Daily Units: 1.13 × 6 hrs = 6.78 kWh
• Monthly Units (30 days): 203 Units
• Monthly Bill @ ₹8.00/unit: ₹1,624.00
5 Practical Steps to Reduce AC Electricity Bills
- 1. Lock the thermostat at 24°C: Running the AC at 24°C instead of 18°C saves ₹700 to ₹1,000 monthly per unit without compromising comfort.
- 2. Pair with a ceiling fan at low speed: A ceiling fan circulating air produces a wind-chill cooling effect, allowing you to raise the AC setpoint to 25°C or 26°C while drawing only 15 to 25 Watts of fan power.
- 3. Clean nylon filters twice a month: Dust accumulation restricts airflow across the evaporator coil, forcing the compressor to run up to 15% longer to cool the room.
- 4. Block solar gain and draft leaks: Heavy blackout curtains on south- and west-facing windows plus foam weatherstripping along door bases prevent hot air infiltration.
- 5. Activate sleep mode overnight: Sleep mode raises the setpoint by 1°C per hour over two hours, reducing overnight compressor runtime by 15% while matching your natural drop in metabolic heat during sleep.