Lighting, LEDs & Electrical Fixtures worked example

Annual Fixture Energy Cost with total connected load of 38 kW: a worked example

Push total connected load up to 38 kW and the picture changes. This example computes every intermediate figure at that operating point. Use this when preparing an energy audit, comparing LED vs. legacy fixture operating cost, building an energy cost model for a facility, justifying an LED upgrade with annual savings, or setting energy budgets for a lighting installation.

The inputs for this scenario

  • Total connected load: 38 kW (raised for this scenario; the documented default is 15)
  • Annual operating hours: 3,500 hr / yr (unchanged)
  • Electricity rate: 0.13 $ / kWh (unchanged)
  • Number of fixtures installed: 100 fixtures (unchanged)

Working through the calculation

  • Applying the documented formula (Annual energy cost = total connected load (kW) x annual operating hours x electricity rate) to the inputs above produces each figure below.
  • At this operating point the engine returns 17,290 $ for annual energy cost, the number this scenario is built around.
  • At this operating point the engine returns 133,000 kWh for annual energy consumed (kwh).
  • At this operating point the engine returns 173 $ / piece for annual energy cost per fixture.
  • At this operating point the engine returns 4.94 $ / hr for hourly energy cost.

How this compares with the baseline

  • Against the tool's baseline example, where total connected load sits at 15 kW and the headline result is 6,825 $, this scenario comes in 153% above the baseline at 17,290 $.
  • It computes the total annual electricity cost of a lighting load and breaks it down to cost per fixture and per hour. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Annual energy cost: 17,290 $ (headline result)
  • Annual energy consumed (kWh): 133,000 kWh
  • Annual energy cost per fixture: 173 $ / piece
  • Hourly energy cost: 4.94 $ / hr

Run it with your numbers

  • Every input above is editable in the live Annual Fixture Energy Cost calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.