Lighting Energy Cost Calculator

Measurements and entries

Record reflectance, maintenance condition, beam definition, and measurement location. A source note beside each entry makes the result reproducible.

Use the displayed unit for every field and document conversions separately. A later annual standby cost decision can draw on Standby Power Cost Calculator.

Annual lighting energy

Default example: 4500 kWh. Enter annual lighting energy in kWh.

Electricity price

Default example: 0.18 $/kWh. Enter electricity price in $/kWh.

Common entry mistakes

Values recorded at different operating points should not share one case.

Recheck decimal placement and unit conversion when the answer looks unusual.

Formula used on this page

The displayed result follows cost = energy × price. The formula draws on Annual lighting energy and Electricity price.

With the current entries, the primary answer is 810.00 $. Preserve the raw inputs when replacing this example.

Calculate annual lighting cost from annual lighting energy and electricity price. Continue to Occupancy Sensor Savings Calculator if annual energy saved is also needed.

What the number means

Interpret Annual lighting cost on the same basis used for the source values. Compare it with initial, maintained, and worst-case lighting conditions.

Save the raw entries before testing another scenario.

Changing Annual lighting energy

Change Annual lighting energy from 4500 kWh to 5400 kWh without altering the remaining fields. The calculated value shifts from 810.00 $ to 972.00 $.

Keep both cases when the changed input represents genuine uncertainty.

Assumptions and limitations

Demand charges and time-varying tariffs are separate.

Additional checks may be needed for daylight variation, control behavior, depreciation, and spatial uniformity. Use measurements, manufacturer data, or another calculation for effects that can change the decision.

Record reflectance, maintenance condition, beam definition, and measurement location.

Before carrying the answer forward

Review electricity price and the remaining entries as one case. If one value belongs to another temperature, load, or time period, separate the scenarios.

The displayed annual lighting cost should be checked against illuminance, uniformity, driver loading, voltage loss, energy use, and maintained output. Investigate an unexpected magnitude before changing the model or adding margin.

If uncertainty remains, calculate labeled low and high cases. Include fixture distribution, reflections, mounting, maintenance, and meter position when those effects can change the decision.

Questions about Lighting Energy Cost