KVAH billing and power factor: why your bill is higher than your usage
If your electricity bill seems high compared with the work your machines do, your power factor is a likely cause. This page explains the idea in plain terms and what you can do about it.
kW, kVA and power factor
kW is the useful power that does real work: turning a motor, running a lathe, cooling a room. kVA is the total power your site draws from the grid. Motors, transformers and fluorescent fittings also draw reactive power (kVAR) to build their magnetic fields. That power does no work but still flows through your wires and meter.
Power factor is the ratio of kW to kVA. A value of 1.0 means nothing is wasted. The lower it falls, the more extra current you draw for the same work.
What KVAH billing means
A traditional meter records kWh, the useful energy. A KVAH meter records apparent energy, which includes the reactive part. When a tariff is based on kVAh, a low power factor raises the units you are billed for. Some tariffs also add penalties for low power factor, or give incentives for a high one.
Which rule applies to you depends on your consumer category, your utility and its current tariff order. Your bill shows the details, and we can read it with you.
How power factor correction works
Capacitors supply the reactive power locally, so it no longer has to come from the grid. An automatic power factor correction (APFC) panel measures your load and switches capacitor steps in and out as it changes. This keeps the power factor near the target all day without manual adjustment.
| Power factor | kVA drawn for 100 kW load | Extra over real load |
|---|---|---|
| 0.70 | 143 | 43% |
| 0.80 | 125 | 25% |
| 0.90 | 111 | 11% |
| 0.98 | 102 | 2% |
Signs your site may need correction
- Your bill shows a power factor below 0.95, or a low-PF penalty line.
- Your kVAh units are noticeably higher than your kWh units.
- You run many motors, pumps, compressors, lifts or HVAC units.
- You have an existing capacitor bank that has not been serviced in years. Capacitors age and lose capacity.
What to do next
Send us a recent electricity bill. We will check your power factor, explain what your tariff does with it, and tell you honestly whether correction is worth it for your site.