1. What is Kilowatt-Hour (kWh)?

The kilowatt-hour (kWh) is a unit of energy equal to one kilowatt (1 kW) of power expended for one hour (1 h) of time. It's the standard measurement used by utility companies to determine electricity consumption on your bill.

2. How Does the Calculator Work?

The calculator uses the following formula:

For three-phase systems, multiply by √3 (≈1.732):

Where:

• \( V \) — Voltage (volts)
• \( I \) — Current (amps)
• \( PF \) — Power factor (unitless, 0 to 1)
• \( h \) — Time duration (hours)

Explanation: The formula calculates energy consumption by multiplying power (voltage × current × power factor) by time, then converting to kilowatt-hours.

3. Importance of kWh Calculation

Details: Calculating kWh helps estimate energy consumption, predict electricity costs, size solar power systems, and evaluate energy efficiency of electrical devices.

4. Using the Calculator

Tips:

• For single-phase systems (most residential), use the single-phase option
• For three-phase systems (commercial/industrial), use the three-phase option
• Power factor is 1 for purely resistive loads (heaters, incandescent lights)
• Power factor is typically 0.8-0.95 for motors and inductive loads

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between kW and kWh?
A: kW (kilowatt) measures power (energy per unit time), while kWh (kilowatt-hour) measures energy (power × time).

Q2: How do I convert kWh to cost?
A: Multiply kWh by your electricity rate (e.g., 10 kWh × $0.15/kWh = $1.50).

Q3: Why does three-phase use √3?
A: In balanced three-phase systems, the total power is the sum of three phases 120° apart, resulting in the √3 factor.

Q4: What if I don't know the power factor?
A: For rough estimates, use 1 for resistive loads or 0.85 for inductive loads. For accurate results, measure it.

Q5: Can I use this for DC circuits?
A: Yes, for DC set power factor to 1 (DC has no reactive power) and use single-phase.