1. What is Water Pump Horsepower?

Water pump horsepower (HP) is the power required to move a specific volume of fluid against a given head pressure, taking into account the fluid's specific gravity and the pump's efficiency.

2. How Does the Calculator Work?

The calculator uses the water pump horsepower formula:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total head in feet (ft)
• \( SG \) — Specific gravity of the fluid (1 for water)
• \( \eta \) — Pump efficiency as a decimal (0-1)
• 3960 — Conversion factor to horsepower

Explanation: The formula calculates the theoretical power required to move the fluid, then divides by the pump's efficiency to get actual required horsepower.

3. Importance of Pump Horsepower Calculation

Details: Proper horsepower calculation ensures you select a pump with adequate power for your application while avoiding oversized pumps that waste energy.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1 for water), and pump efficiency (typically 0.7-0.9 for centrifugal pumps). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical pump efficiency value?
A: Centrifugal pumps typically have 70-90% efficiency (0.7-0.9), while positive displacement pumps can reach 90% or higher.

Q2: How do I determine total head?
A: Total head is the sum of static head (vertical distance) and friction head (pressure loss due to piping).

Q3: What if I'm pumping something other than water?
A: Use the specific gravity of your fluid (SG = density of fluid / density of water).

Q4: Should I add a safety factor?
A: It's common to add 10-20% to the calculated HP to account for system variations and future needs.

Q5: How does this relate to motor horsepower?
A: Motor HP should be equal to or greater than pump HP, considering any additional factors like motor efficiency.