New: 600 kWh ➤ This part of the bill should go down proportionally.
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2. Power Factor (PF)
• Pulse-start MH fixtures typically have a PF > 0.9 (especially if they’re CWA ballasts), meaning they draw real power efficiently. • LED drivers vary. Many cheaper or lower-quality LEDs have a power factor between 0.7 and 0.9.
o If your 600W LED has a PF of 0.8, it actually draws:
▪ Apparent Power = 600W / 0.8 = 750 VA
o Utilities may charge for kVA demand or penalize for low PF (depends on your rate structure).
o ➤ Poor PF = higher apparent demand and potential surcharges.
3. In-Rush Current
• LED drivers often have high in-rush current when first powered on — sometimes 20– 50x normal current for a few milliseconds.
• Usually NOT billed directly, since meters average usage over time. However:
o If all fixtures switch on at once, the spike might impact your demand charge, depending on your utility’s metering window.
o Metal halides have warm-up time and don’t exhibit sharp in-rush peaks.
• Demand Charges (kW) • Many utilities charge based on peak 15-minute (or 30-minute) usage window each month. • If all your LED floods are switched on simultaneously and cause a high momentary demand (due to in-rush or load peaking), your demand charge may not drop as much as your energy usage (kWh) does. • ➤ Staggering startup or using soft-start drivers can help.
5. Other Possible Issues
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