Greenhouse, Indoor Farming & Agri-Processing worked example

Grow Light Energy Cost at 43% effective lit hours over the period: a worked example

Suppose effective lit hours over the period falls to 43%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate the monthly or per-cycle electricity cost of LED or HPS grow lights in a greenhouse, vertical farm, or indoor grow room from fixture count, photoperiod, utility rate, and a daylight credit so growers can budget energy spend per crop.

The inputs for this scenario

  • Total connected grow light load: 65 kW (held at the documented default)
  • Cost per kWh of electricity: 0.12 $ / kWh (held at the documented default)
  • Effective lit hours over the period: 43 % (the input this scenario stresses; the baseline uses 60)
  • Fixed demand and meter charges: 250 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Variable lighting energy cost = total connected grow light load × cost per kWh × effective lit hours over the period.
  • Total grow light energy cost works out to 253 $ at these inputs, and this is the headline figure for the scenario.
  • Lighting cost per kW of canopy works out to 3.9 $ / piece at these inputs.
  • Variable lighting energy cost works out to 3.35 $ at these inputs.
  • Fixed demand and meter charges works out to 250 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where effective lit hours over the period sits at 60% and the headline result is 255 $, this scenario comes in 0.52% below the baseline at 253 $.
  • It computes total grow light electricity cost by adding the variable energy cost (connected load times rate times effective lit-hour share) to fixed demand and meter charges. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Total grow light energy cost: 253 $ (headline result)
  • Lighting cost per kW of canopy: 3.9 $ / piece
  • Variable lighting energy cost: 3.35 $
  • Fixed demand and meter charges: 250 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Grow Light Energy Cost calculator, set effective lit hours over the period to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.