HVAC Ductwork, Air Handling & Mechanical Products worked example

Rework Cost at 3.6% rework rate: a worked example in hvac ductwork, air handling & mechanical products

Here is what the math looks like when conditions slip. We hold every other input steady and drop rework rate to 3.6%, then walk the calculation through step by step. Estimate the total rework cost for ductwork fabrication or air handling unit production. Enter total units produced, rework cost per event, the rework rate, and fixed rework area overhead to calculate total rework exposure and rework cost per good unit.

The inputs for this scenario

  • Duct sections or AHU assemblies produced: 200 units (held at the documented default)
  • Average rework cost per event: 85 $ / event (held at the documented default)
  • Rework rate: 3.6 % (the input this scenario stresses; the baseline uses 5)
  • Fixed rework area overhead per period: 600 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Variable rework cost = units produced × rework rate × cost per event.
  • Weighted cost works out to 1,212 $ at these inputs, and this is the headline figure for the scenario.
  • Per piece value works out to 6.06 $ / piece at these inputs.
  • Captured value works out to 612 $ at these inputs.
  • Fixed adjustment works out to 600 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where rework rate sits at 5% and the headline result is 1,450 $, this scenario comes in 16.41% below the baseline at 1,212 $.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to rework rate, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It treats every rework event as the same average cost; a single major AHU teardown can cost far more than the average, so high-variance defects need event-level costing rather than a flat per-event figure.

Results at a glance

  • Weighted cost: 1,212 $ (headline result)
  • Per piece value: 6.06 $ / piece
  • Captured value: 612 $
  • Fixed adjustment: 600 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Rework Cost calculator, set rework rate to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.