AC Cost Per Hour Calculator
Estimate the cost to run your air conditioning unit for one hour.
Enter your AC unit's power consumption in Kilowatts (kW) and your electricity rate in Dollars per Kilowatt-Hour ($/kWh).
Enter AC Details
Understanding AC Electricity Cost
How is AC Electricity Cost Calculated?
Electricity cost is typically measured in kilowatt-hours (kWh). A kilowatt-hour is the energy used by consuming one kilowatt (kW) of power for one hour.
The simple formula for calculating the cost for one hour is:
Cost per Hour = Power (kW) × Rate ($/kWh)
This calculator applies this direct formula to give you a quick estimate.
Where to Find Your Numbers
- AC Power Consumption (kW): Check the nameplate label on the unit (often on the side, back, or near the power cord), the owner's manual, or the manufacturer's website. It's usually listed in Watts (W) or Kilowatts (kW). Remember to convert Watts to Kilowatts by dividing by 1000.
- Electricity Rate ($/kWh): This is found on your electricity bill. Look for a line item like "Energy Charge" or "Generation Charge" that lists the cost per kWh. Rates can vary based on time of day, usage tiers, or season. Use your average rate or the rate applicable during peak AC usage times for a better estimate. Remember to convert Cents/kWh to Dollars/kWh by dividing by 100.
Factors Affecting Actual Cost
This calculator provides a baseline estimate. Your actual cost might differ due to:
- Compressor Cycling: AC units don't run at full power constantly. The compressor cycles on and off to maintain temperature, using less power overall than if running continuously.
- Fan-Only Mode: Running just the fan uses significantly less power than running the compressor.
- Variable Speed Units: Modern inverter-based ACs adjust power consumption based on cooling needs, often running at lower power levels.
- Tiered Rates & Fees: Your total electricity bill includes other charges like delivery fees, taxes, and potentially higher rates for higher usage tiers, which aren't included in this calculation.
Calculation Examples
Here are some examples illustrating how the calculation works:
Example 1: Standard Window Unit
Scenario: Calculate the cost to run a common window AC unit.
1. Known Values: Power Consumption (kW) = 1.0 kW, Electricity Rate ($/kWh) = $0.12 / kWh.
2. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
3. Calculation: Cost = 1.0 kW × $0.12/kWh = $0.12
4. Result: Estimated Cost Per Hour: $0.12.
Conclusion: Running this AC for one hour costs approximately 12 cents.
Example 2: Large Central AC System
Scenario: Estimate the cost for a larger central AC system.
1. Known Values: Power Consumption (kW) = 3.5 kW, Electricity Rate ($/kWh) = $0.18 / kWh.
2. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
3. Calculation: Cost = 3.5 kW × $0.18/kWh = $0.63
4. Result: Estimated Cost Per Hour: $0.63.
Conclusion: Running this central AC for one hour costs approximately 63 cents.
Example 3: Power in Watts (W)
Scenario: Your unit lists power in Watts.
1. Known Values: Power Consumption (W) = 800 W, Electricity Rate ($/kWh) = $0.14 / kWh.
2. Conversion: Convert Watts to Kilowatts: 800 W / 1000 = 0.8 kW.
3. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
4. Calculation: Cost = 0.8 kW × $0.14/kWh = $0.112
5. Result: Estimated Cost Per Hour: $0.11 (Rounded).
Conclusion: Running this 800W AC costs about 11 cents per hour.
Example 4: Rate in Cents (¢/kWh)
Scenario: Your electricity bill lists the rate in cents.
1. Known Values: Power Consumption (kW) = 1.2 kW, Electricity Rate (¢/kWh) = 16 ¢/kWh.
2. Conversion: Convert Cents/kWh to Dollars/kWh: 16 ¢/kWh / 100 = $0.16 / kWh.
3. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
4. Calculation: Cost = 1.2 kW × $0.16/kWh = $0.192
5. Result: Estimated Cost Per Hour: $0.19 (Rounded).
Conclusion: At 16 cents per kWh, this AC costs about 19 cents per hour.
Example 5: Both Conversions Needed
Scenario: You have Watts and Cents/kWh.
1. Known Values: Power Consumption (W) = 2200 W, Electricity Rate (¢/kWh) = 21 ¢/kWh.
2. Conversions: Power: 2200 W / 1000 = 2.2 kW. Rate: 21 ¢/kWh / 100 = $0.21 / kWh.
3. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
4. Calculation: Cost = 2.2 kW × $0.21/kWh = $0.462
5. Result: Estimated Cost Per Hour: $0.46 (Rounded).
Conclusion: This larger unit costs about 46 cents per hour at this rate.
Example 6: Low Power Unit
Scenario: A small portable AC unit.
1. Known Values: Power Consumption (kW) = 0.6 kW, Electricity Rate ($/kWh) = $0.10 / kWh.
2. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
3. Calculation: Cost = 0.6 kW × $0.10/kWh = $0.06
4. Result: Estimated Cost Per Hour: $0.06.
Conclusion: A low-power unit like this costs about 6 cents per hour.
Example 7: High Electricity Rate
Scenario: Standard AC unit with a high rate.
1. Known Values: Power Consumption (kW) = 1.5 kW, Electricity Rate ($/kWh) = $0.25 / kWh.
2. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
3. Calculation: Cost = 1.5 kW × $0.25/kWh = $0.375
4. Result: Estimated Cost Per Hour: $0.38 (Rounded).
Conclusion: A high electricity rate significantly increases the cost per hour.
Example 8: Calculating for a Day (Manual Step)
Scenario: You want to know the cost for running an AC unit for 8 hours.
1. Known Values: Power Consumption (kW) = 1.0 kW, Electricity Rate ($/kWh) = $0.12 / kWh.
2. Calculate Cost Per Hour (using the tool or Example 1): Cost per Hour = $0.12.
3. Manual Calculation for 8 hours: Total Cost = Cost per Hour × Number of Hours = $0.12/hour × 8 hours = $0.96.
Conclusion: Running this AC for 8 hours would cost about 96 cents.
Example 9: Very Efficient Unit (Approx)
Scenario: A modern, energy-efficient AC unit.
1. Known Values: Power Consumption (kW) = 0.9 kW, Electricity Rate ($/kWh) = $0.13 / kWh.
2. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
3. Calculation: Cost = 0.9 kW × $0.13/kWh = $0.117
4. Result: Estimated Cost Per Hour: $0.12 (Rounded).
Conclusion: More efficient units use less power, resulting in a lower hourly cost.
Example 10: Rounding
Scenario: An example demonstrating rounding to two decimal places.
1. Known Values: Power Consumption (kW) = 1.1 kW, Electricity Rate ($/kWh) = $0.175 / kWh.
2. Formula: Cost per Hour = Power (kW) × Rate ($/kWh)
3. Calculation: Cost = 1.1 kW × $0.175/kWh = $0.1925
4. Result: Estimated Cost Per Hour: $0.19 (Rounded to two decimal places).
Conclusion: The calculator rounds the final cost to two decimal places for currency display.
Frequently Asked Questions about AC Cost
1. What does this calculator estimate?
It estimates the direct electricity cost of running an air conditioning unit for one hour, based on its stated power consumption and your electricity rate.
2. What inputs are needed?
You need the AC unit's power consumption in Kilowatts (kW) and your electricity rate in Dollars per Kilowatt-Hour ($/kWh).
3. Where can I find my AC's power consumption (kW)?
Look on the unit's label, in the owner's manual, or online specifications. It may be listed as Power Input or Consumption in Watts (W) or Kilowatts (kW).
4. How do I convert Watts (W) to Kilowatts (kW)?
Divide the value in Watts by 1000. For example, 1200 W is 1.2 kW.
5. Where do I find my electricity rate ($/kWh)?
On your electricity bill. Look for the energy or generation charge rate per kilowatt-hour (kWh). It might be shown in dollars ($) or cents (¢).
6. How do I convert Cents per kWh (¢/kWh) to Dollars per kWh ($/kWh)?
Divide the value in cents by 100. For example, 18 ¢/kWh is $0.18/kWh.
7. Is this estimate perfectly accurate?
No, it's an estimate. It assumes the AC runs at its maximum power draw for the full hour and uses a single rate. Actual costs can vary based on cycling, fan-only use, variable speed operation, and your utility's specific billing structure (like tiered rates or time-of-use rates).
8. Does this include delivery fees, taxes, or other bill charges?
No, this calculator focuses only on the direct energy cost based on power consumption and the energy rate. Your total electricity bill includes other components.
9. Can I use this to estimate the cost for a day or a month?
Yes, once you have the cost per hour, you can multiply it by the number of hours the AC runs in a day or month for a rough estimate. Be mindful that AC usage varies.
10. What if my AC unit has different power consumptions for different modes?
Use the maximum listed power consumption for the cooling mode to calculate the highest potential hourly cost. If you know the power draw for lower settings or fan-only, you could perform separate calculations.
