Technical meaning
- Operating hours describe the time a lighting group is on during a day, year or defined period.
- The note should state whether the hours are manual switching, scheduled operation, occupancy behaviour or a control assumption.
Calculation use
- Annual kWh equals connected load in kilowatts multiplied by operating hours per year.
- Energy-savings estimates compare old and new loads under the same or clearly separated operating-hour assumptions.
Not the same as
- Operating hours are not occupancy by themselves. A room may be occupied while only part of the lighting is on.
- Operating hours are not a tariff. Cost still depends on the entered cents per kWh.
Australian context
- Australian lighting energy notes should keep operating hours, zone boundaries and control assumptions visible beside the annual kWh result.
Examples
| Example | Value | Planning note |
|---|
| Residential evening room | 3 h/day | A compact schedule for a small energy estimate. |
|---|
| Office weekday zone | 10 h/day, 5 days/week | Annual days should match the actual use note. |
|---|
| After-hours security group | overnight schedule | Distinct from normal occupied lighting when load and purpose differ. |
|---|
Calculation limits and records
- Operating-hour calculations are low-risk arithmetic. Real annual cost depends on the entered rate, schedule and control condition.