HVAC Ductwork, Air Handling & Mechanical Products worked example

Rework Cost at 5.75% rework rate: a worked example in hvac ductwork, air handling & mechanical products

Push rework rate up to 5.75% and the picture changes. This example computes every intermediate figure at that operating point. Use this when reviewing the quality cost of your ductwork fabrication or AHU assembly operation. Rework on ductwork may include re-sealing leaking joints, re-cutting off-size sections, re-rolling seams, re-forming flanges, or re-brazing leaking coil connections. Quantifying the rework cost per good unit helps justify investment in process improvements, better tooling, or operator training.

The inputs for this scenario

  • Duct sections or AHU assemblies produced: 200 units (unchanged)
  • Average rework cost per event: 85 $ / event (unchanged)
  • Rework rate: 5.75 % (raised for this scenario; the documented default is 5)
  • Fixed rework area overhead per period: 600 $ (unchanged)

Working through the calculation

  • Applying the documented formula (Variable rework cost = units produced × rework rate × cost per event) to the inputs above produces each figure below.
  • At this operating point the engine returns 1,578 $ for weighted cost, the number this scenario is built around.
  • At this operating point the engine returns 7.89 $ / piece for per piece value.
  • At this operating point the engine returns 978 $ for captured value.
  • At this operating point the engine returns 600 $ for fixed adjustment.

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 8.79% above the baseline at 1,578 $.
  • It computes variable rework cost from units, rework rate and cost per event, adds fixed rework overhead, and divides the total over good units to give cost per good unit. 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

  • Weighted cost: 1,578 $ (headline result)
  • Per piece value: 7.89 $ / piece
  • Captured value: 978 $
  • Fixed adjustment: 600 $

Run it with your numbers

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

Last reviewed 2026-05-12.