Question

What is the estimated cost of operating a 3.5 hp water pump for 8 hours, given an electricity rate of 9 cents per kilowatt-hour?

Answer 1

To calculate the estimated cost of operating a 3.5 hp water pump for 8 hours, we first need to convert horsepower to kilowatts, then calculate the energy consumed, and finally determine the cost based on the electricity rate.

1. **Convert horsepower to kilowatts:**
\[
1 \text{ hp} = 0.746 \text{ kW}
\]
Therefore,
\[
3.5 \text{ hp} = 3.5 \times 0.746 \text{ kW} \approx 2.610 \text{ kW}
\]

2. **Calculate the energy consumed in kilowatt-hours (kWh):**
Operating the pump for 8 hours:
\[
\text{Energy (kWh)} = \text{Power (kW)} \times \text{Time (hours)}
\]
\[
\text{Energy} = 2.610 \text{ kW} \times 8 \text{ hours} \approx 20.88 \text{ kWh}
\]

3. **Calculate the total cost of operating the pump:**
With an electricity rate of 9 cents per kWh:
\[
\text{Cost} = \text{Energy (kWh)} \times \text{Rate (cents per kWh)}
\]
\[
\text{Cost} = 20.88 \text{ kWh} \times 0.09 \text{ dollars per kWh} \approx 1.8792 \text{ dollars}
\]

So, the estimated cost of operating the 3.5 hp water pump for 8 hours is approximately **$1.88**.