Lighting, LEDs & Electrical Fixtures worked example

Driver Failure Cost at 1.08% expected driver failure rate: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop expected driver failure rate to 1.08%, then walk the calculation through step by step. Estimate total warranty and field replacement cost from LED driver failures in an installed fixture population. Combines the number of installed fixtures, driver replacement cost per failure, the expected driver failure rate, and fixed warranty administration costs.

The inputs for this scenario

  • Fixtures under warranty: 5,000 fixtures (held at the documented default)
  • Driver replacement cost per failure: 75 $ / failure (held at the documented default)
  • Expected driver failure rate: 1.08 % (the input this scenario stresses; the baseline uses 1.5)
  • Fixed warranty administration cost: 800 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Variable warranty cost = fixtures under warranty x replacement cost per failure x expected failure rate%.
  • Total driver failure warranty cost works out to 4,850 $ at these inputs, and this is the headline figure for the scenario.
  • Cost per failed driver works out to 0.97 $ / piece at these inputs.
  • Variable warranty cost works out to 4,050 $ at these inputs.
  • Fixed warranty admin cost works out to 800 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where expected driver failure rate sits at 1.5% and the headline result is 6,425 $, this scenario comes in 24.51% below the baseline at 4,850 $.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to expected driver failure rate, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes a single flat failure rate over the period; real driver failures follow a bathtub curve with early infant-mortality and end-of-life spikes, so a flat rate understates risk near warranty expiry.

Results at a glance

  • Total driver failure warranty cost: 4,850 $ (headline result)
  • Cost per failed driver: 0.97 $ / piece
  • Variable warranty cost: 4,050 $
  • Fixed warranty admin cost: 800 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Driver Failure Cost calculator, set expected driver failure rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.