How much does it cost to run an LED light bulb for 24 hours?

The cost of running an LED light bulb for 24 hours depends on the wattage of the bulb, the electricity rate in your area (usually measured in kilowatt-hours or kWh), and how much electricity the bulb uses.

Steps to Calculate the Cost:

1. Determine the power usage of the LED bulb:

   • LED bulbs are usually rated in watts (W). For example, a standard LED bulb might use 9 watts of power (equivalent to a 60W incandescent bulb).

2. Convert the power usage to kilowatt-hours (kWh):

   • 1 kilowatt (kW) = 1,000 watts (W).
   • To convert watts to kilowatts: $$\text{Power in kWh} = \frac{\text{Power in watts}}{1000}$$
   • For a 9W LED bulb: $$\frac{9 \text{ watts}}{1000} = 0.009 \text{ kW}$$

3. Multiply the power in kWh by the number of hours:

   • To find the total energy consumption for 24 hours: $$\text{Energy used in 24 hours} = \text{Power in kWh} \times \text{Hours of use}$$ $$0.009 \text{ kW} \times 24 \text{ hours} = 0.216 \text{ kWh}$$

4. Multiply by the electricity rate:

   • Electricity rates vary by location, but in the U.S., the average cost of electricity is around $0.13 per kWh (it can range from $0.09 to $0.20 depending on your region).
   • So, the cost to run the 9W LED bulb for 24 hours would be: $$0.216 \text{ kWh} \times 0.13 \text{ dollars/kWh} = 0.02808 \text{ dollars}$$ or about 2.8 cents.

Summary:

• For a 9W LED bulb running for 24 hours, the cost would be around 2.8 cents (if electricity costs $0.13 per kWh).
• Lower-wattage bulbs (e.g., 5W) would cost even less, while higher-wattage bulbs (e.g., 15W or 20W) would cost slightly more.

Example Costs:

• 9W LED bulb: 2.8 cents for 24 hours.
• 15W LED bulb: $$0.015 \text{ kW} \times 24 \text{ hours} = 0.36 \text{ kWh} \times 0.13 \text{ dollars/kWh} = 0.0468 \text{ dollars} \approx 4.7 \text{ cents}$$ (about 4.7 cents for 24 hours).