Calculator
kVAR calculator and power-factor bill check
Size the capacitors needed to reach a target power factor, see how your utility treats power factor, and send us a bill if you want a real answer for your facility.
Size the kVAR
The formula
For a steady load P (kW), moving from power factor p₁ to p₂ (both lagging, displacement):
kVAR = P × [tan(arccos p₁) − tan(arccos p₂)]
Worked example: 500 kW at 0.80 has tan(arccos 0.80) = 0.75, so it draws 375 kVAR. At 0.95, tan(arccos 0.95) ≈ 0.329, or about 164 kVAR. The difference is about 211 kVAR. Apparent power falls from 625 kVA to about 526 kVA.
Why there's no dollar figure
Utilities calculate power-factor charges in very different ways: on peak or average power factor, per kVAR or through billed demand, with or without credits, minimums and ratchets. Many smaller customers pay nothing at all. A dollar estimate built from two numbers would be wrong too often, so we offer a free bill review instead.
Free bill review
Send us one to twelve recent electric bills. We'll read your utility's current rate schedule and tell you:
- whether you're paying anything for power factor today, and how much;
- what correcting it would be worth, including capacity and voltage benefits where there's no penalty;
- whether harmonics or drives mean you should measure before buying anything.
Email your bill to Call 1-800-FIX-KVAR
Or use the contact form on GrossAutomation.com.