Quick answer: A true 1000W fixture uses 1 kWh for every hour it runs at full power. At 12 hours per day that is about 12 kWh/day or 360 kWh over 30 days; at 18 hours it is about 18 kWh/day or 540 kWh over 30 days.
This guide covers 1000W LED grow light power usage, 1000 watt light power consumption, monthly running cost, how much electricity a grow light uses, and the grow light electricity calculator formula. Check actual AC input power. A product marketed as “1000W equivalent” may draw far less, while TheOneGrow's 1000W model lists a 1000W AC input.
1000W LED grow light power-usage table
| Daily runtime | Daily energy | 30-day energy |
|---|---|---|
| 12 hours | 12 kWh | 360 kWh |
| 18 hours | 18 kWh |