Connected load becomes energy only after time is named
Connected load is the input power of the lighting group. Annual kWh is the energy note after that load is combined with operating hours. The difference matters because two rooms can have the same connected watts and very different annual energy when their schedules differ.
For lighting estimates, keep the load, zone and time basis together. The lighting power density calculator calculates connected load and W/m2 when count, watts and area are known. The connected load note table names the group and input watts. The annual lighting kWh formulas table keeps the arithmetic visible. The operating-hours lighting schedule table keeps the time basis from being guessed later.
When the existing condition needs to be preserved before comparison, keep it beside lighting energy baseline notes. That page keeps connected load, hours, control state and measured-light notes together before annual kWh or W/m2 values are compared.
Match the job to the owner page
Different lighting notes answer different questions. Keep this page focused on load-to-kWh conversion, then send the rest of the note to the page that owns it.
| User job | Keep on this page | Owner page for the rest |
|---|---|---|
| Turn known connected watts into annual kWh. | Lighting group, connected load, annual hours and kWh arithmetic. | Annual lighting kWh formulas table |
| Separate fixture count from energy use. | Count and input watts only where they form the connected load. | Fixture count lighting schedule |
| Preserve an existing condition before a change. | Existing load, actual hours and control state. | Lighting energy baseline notes |
| Name the operating-hours basis. | Annual hours attached to the same load row. | Operating-hours lighting schedule table |
| Split full output, dimmed and sensor states. | One kWh row for each named control state. | Lighting control kWh assumptions table |
| Check whether the lighting output still matches the task note. | The energy row only, with a note that output is a separate check. | Lumens to lux calculator and lux meter reading notes |
| Compare connected watts against floor area. | Connected watts and the named area boundary. | Lighting power density calculator and lighting power density examples |
| Compare annual kWh with an entered energy rate. | Annual kWh and any existing/proposed kWh difference. | Energy savings calculator |
| Describe dimming, sensors or daylight response. | State names and hours for each energy row. | Lighting control kWh assumptions table |
| Note lane | What to write | Follow-up page |
|---|---|---|
| Connected-load note | Room, row, shelf, counter, aisle or exterior group, with count and input watts. | The connected load note table keeps the watts and group boundary together. |
| Operating-hours note | Hours per day, days per year, annual hours, rostered periods or seasonal row. | The operating-hours lighting schedule table keeps the time basis visible. |
| Control-state note | Full output, dimmed state, daylight response, sensor state or after-hours mode. | The lighting control kWh assumptions table keeps state names beside energy rows. |
| LPD note | Connected watts, area boundary and W/m2 only. | The lighting power density calculator owns the density comparison. |
| Visual-performance handoff | Note whether lux, glare, colour appearance or daylight adequacy still needs a separate check. | The output, LPD and lux pages own those notes; the kWh row does not settle them. |
Formula note
The simple energy relationship is:
| Calculation | Formula | Example |
|---|---|---|
| Connected kW | watts / 1,000 | 240 W = 0.24 kW |
| Daily kWh | connected kW x hours per day | 0.24 kW x 6 h = 1.44 kWh/day |
| Annual kWh | connected kW x annual hours | 0.24 kW x 1,200 h = 288 kWh/year |
| Group change | existing annual kWh minus proposed annual kWh | 520 kWh - 310 kWh = 210 kWh difference |
This arithmetic stays useful only when the group boundary is stable. A room-lighting estimate, a replacement estimate and a running-cost row should all describe the same lighting group before their numbers are compared.
Build the load row first
Start with the fittings that operate together. A desk row, kitchen bench group, display wall or warehouse aisle may need its own line even when it sits inside a larger room. The fixture count calculator can turn a required lumen allowance into a count. The luminaire output note table keeps lumens, watts, optics and colour fields beside that count.
| Load field | Example | Check beside it |
|---|---|---|
| Count | 12 luminaires | The count belongs to one lighting group. |
| Input watts | 18 W each | Luminaire data and driver grouping are not hidden. |
| Connected load | 216 W total | Watts are not treated as brightness. |
| Connected kW | 0.216 kW | The value is ready for annual-hour multiplication. |
If the proposed fitting count changes the light level, keep that visible. A lower connected load can still reduce the useful illuminance on the task plane. The lumens to lux calculator can check an output scenario when installed lumens are known.
Label the point, plane and condition
A kWh row is easier to trust when the note says which part of the site it describes. Point labels help meter readings, plane labels help visual checks and condition labels help energy rows.
| Label | Example entry | Why it belongs beside the kWh row |
|---|---|---|
| Point label | Office north desk row P1, corridor door P2 or warehouse aisle bay P3. | Later readings can be matched to the same place. |
| Plane label | Desktop plane, aisle floor, bench surface or vertical display face. | Energy notes do not replace the surface being lit. |
| Condition label | Existing full output, proposed dimmed state or after-hours sensor state. | The same connected load may not run at the same level all year. |
| Load label | 12 x 18 W fittings, 216 W connected load. | Fixture count and connected watts stay distinct from kWh. |
| Time label | 1,200 h/year based on the named row. | Annual kWh is not guessed from whole-building hours. |
These labels are a practical note of the load, operating state and surface assumptions used for the energy calculation. They do not verify lighting quality or settle the task-lighting note for the space.
Split the note when the operating story changes
One connected load can produce several annual kWh rows when the lighting group has more than one operating state. A restaurant dining area may have setup, service and cleaning scenes. A strata corridor may have normal movement, low night mode and maintenance override. A warehouse aisle may have picking hours and security lighting.
| Operating story | Separate row to keep | Reason |
|---|---|---|
| Occupied and cleaning periods differ. | Normal occupied load and cleaning override load. | Hours and scene level are not the same. |
| Sensors reduce after-hours operation. | Full-load capacity and expected sensor state. | Connected load is not the same as annual energy. |
| Daylight-linked rows dim near windows. | Window-side control zone and internal control zone. | The daylight condition changes the load basis. |
| Seasonal or rostered use applies. | Main season, closure period or limited-use row. | Annual days need a named basis. |
| Manual dimming is recorded. | Full-output allowance and selected dimmed state. | A dimmed row needs its own load factor and hours. |
This keeps the energy note closer to how Australian buildings are actually operated. The kWh line can then be read beside the control note rather than being treated as a flat all-year load.
| Schedule row | Load basis | Hours basis | kWh boundary |
|---|---|---|---|
| Existing office desk row | 10 x 32 W panels, 320 W connected load. | Weekday occupied hours plus cleaning row. | Existing kWh for that desk row only. |
| Proposed office desk row | 8 x 24 W panels, 192 W connected load. | Same occupied hours, dimmed daylight row separated. | Proposed kWh before any cost comparison. |
| Corridor night state | Same installed group, reduced-output state named. | Night period from operating-hours note. | Sensor or dimming assumption stated beside the row. |
| Warehouse aisle security state | Security fittings or reduced high-bay state named. | Closed-hours row, not picking hours. | Energy row kept distinct from task-lighting check. |
Match hours to the same zone
Operating hours should not be borrowed from the whole building unless the same lighting group actually follows that schedule. Kitchens, offices, warehouses and shared areas often have normal hours, cleaning periods, security rows and reduced-output states.
| Hours note | Better entry | Weak entry |
|---|---|---|
| Office perimeter row | Occupied weekdays, daylight-side row, after-hours cleaning separated. | Whole tenancy hours applied to every fitting. |
| Kitchen bench group | Evening task periods distinct from ambient scene. | Kitchen lighting treated as one flat schedule. |
| Warehouse aisle | Picking hours and security mode separated. | All high-bays given the same full-output year. |
| Exterior entry | Dusk pattern and sensor state recorded. | Outdoor lights assumed to run every night at full output. |
The lighting control kWh assumptions table is useful when the energy row depends on dimming, daylight response or fallback operation.
Separate kWh from cost
Annual kWh is not the same as a bill. Cost needs a rate chosen by the person making the estimate, and many accounts include charges that are outside a simple lighting row. The energy savings calculator can hold an entered rate for a quick comparison, but the kWh note should remain visible on its own.
| Quantity | What it can say | What stays outside |
|---|---|---|
| Connected load | Input watts for one group. | Lux on the named plane, glare and colour quality. |
| Annual kWh | Energy from recorded load and hours. | Account charges, demand items and rebates. |
| Cost case | kWh multiplied by an entered rate. | Future account outcome or funding decision. |
| Replacement difference | Existing kWh compared with proposed kWh. | Maintenance scope, installation allowance and handover notes. |
Keep the visual check beside the energy row
Energy notes should not erase the lighting task. A replacement may save kWh while changing output, beam spread, colour appearance or glare. Keep the lighting power density example table and lux meter reading notes close to the energy note when the result will be compared later.
| Energy row | Companion lighting check | Related page |
|---|---|---|
| Lower connected watts | Installed lumens and measured plane. | Luminaire output notes |
| Different count | Spacing, beam and overshoot. | Fixture count lighting schedule |
| Different hours | Lighting zone and control state. | Lighting control zones and operating hours |
| Different area | Load density and task plane. | Lighting power density examples |
| Different dimming state | State name, hours and load factor. | Lighting control kWh assumptions |