Auditing a 3-story office building in Atlanta on Georgia Power. The building has a power factor penalty on every bill — PF reads between 0.78 and 0.83. But the building is mostly office space with computers, lighting, and light HVAC. No heavy motors, no industrial equipment. How does an office building end up with a power factor below 0.85?
Power factor penalty on a building with no motors — how?
Fluorescent lighting ballasts. If the building still has older magnetic ballasts on the fluorescent lights, those are highly inductive and will drag the power factor down. A building with hundreds of magnetic ballast fixtures can easily have a PF in the 0.75-0.85 range. Electronic ballasts and LED fixtures have much better power factor. Also check for UPS systems and older computer power supplies — those can have poor power factor too.
Another culprit: elevator motors. Even in a low-rise building, the elevator motor is often the largest single load and older elevator motors have terrible power factor. If this building has 2-3 elevators with older motors, that alone could explain the PF penalty.
Derek and Mike both raise valid causes. But before you chase the operational fix, check whether the penalty is being calculated correctly. Verify the PF threshold in the tariff (Georgia Power uses 0.85 for most commercial accounts) and verify the penalty formula. I've found cases where the billing system applied the wrong penalty formula or used the wrong threshold. If the penalty calculation itself is correct, then the operational fix — replacing magnetic ballasts with electronic ones or adding capacitor banks — is the client's decision, not an audit finding per se. But quantifying the penalty cost helps them make the investment decision.
Checked the penalty calculation — it's correct. Building is full of old magnetic ballasts from the 1990s. The landlord is already planning a lighting retrofit so the PF issue should resolve itself. Good to know for future reference though — office buildings CAN have PF problems.