Power factor penalties: reading the kVAR line
What kVAR and kVA mean on a commercial bill, how utilities penalize low power factor, and how to tell a real penalty from a billing or metering error.
Vikram Rao · May 12, 2026 · 7 min read
Key takeaways
- Power factor is real power (kW) divided by apparent power (kVA); the kVAR line shows the reactive component that drags it down.
- Utilities apply the penalty in different ways: billing on kVA, scaling kW demand by a power factor ratio, or charging for excess reactive energy.
- A sudden penalty after years of none usually points to a failed capacitor bank, a metering change or a billing setup error.
Three kinds of power on one bill
Motors, compressors, transformers and some lighting ballasts draw two kinds of current. One does useful work, measured in kilowatts (kW). The other builds and collapses magnetic fields and does no work, measured in kilovolt-amperes reactive (kVAR). The utility's equipment has to carry both. Apparent power, in kilovolt-amperes (kVA), is the combination of the two: kVA is the square root of kW squared plus kVAR squared.
Power factor is kW divided by kVA. A facility with a power factor of 0.95 draws a modest amount of reactive power. At 0.80, the utility must deliver noticeably more current for the same useful load, which costs it capacity in wires and transformers. That is the reason tariffs charge for low power factor.
How tariffs apply the charge
There is no single method. Some tariffs bill demand on kVA instead of kW, which penalizes poor power factor automatically. Some compute billing demand as measured kW multiplied by a reference power factor (often 0.85 or 0.90, depending on the utility) divided by the actual power factor, whenever the actual falls below the reference. Others bill a separate charge per kVAR or per kVARh of reactive energy beyond a threshold.
Many tariffs apply the provision only to larger demand-metered schedules, and some only to lagging power factor, which is the usual condition for inductive loads. Reading the tariff section for the account's schedule is the first step, because a penalty on a bill under a schedule that has no such provision is a clear error.
Reading the line on the bill
Look for a measured kVAR or kVA value, a computed power factor, and an adjustment line. Some bills print all three. Others show only the adjustment, and the underlying kVAR must come from the meter data or the utility's customer portal. Reconstruct it: take the kW and the kVAR for the interval of peak demand, calculate the power factor, apply the tariff formula, and compare to what the bill charged.
A common discrepancy is that the utility computes power factor at the time of maximum kW demand, while the customer's own monitoring uses a monthly average. They can differ meaningfully. The tariff says which applies, and the bill should follow it.
Why a penalty appears where none existed
A site that had no penalty for years and suddenly does usually has a physical or a data explanation. Physical causes include a failed capacitor bank or a blown capacitor fuse, a new variable-frequency drive or compressor with poor displacement characteristics, or a change in how loads are staged. Data causes include a meter replacement with a different configuration, a changed current transformer ratio on only one of the measurement channels, or a billing system that began applying the provision after an account migration.
Leading power factor, caused by overcorrection from capacitors at light load, can also be penalized in some tariffs, so a site that added capacitors and sees a new charge should check for this condition rather than assume more correction is better.
Correct the bill, then fix the cause
If the penalty is invalid, the claim package is the bill, the tariff section, a calculation using the metered kW and kVAR, and any meter change records. If it is valid, the refund opportunity may be nil, but the saving from correcting the power factor can pay back quickly. A capacitor bank sized and installed correctly often costs less than a year of penalty.
Either way, put a power factor column in the monthly review for demand-metered accounts. It costs nothing to track and makes a developing problem visible months before it becomes a standing charge.