What claim rate should I assume?

Mature PEMFC programs run 1 to 5 percent claim rate over a 5-year warranty. New SOFC, SOEC, or PAFC programs often see 5 to 12 percent in early years until field hours build up.

Should I use list price or cost for claim service cost?

Use cost (your spend, not customer price). Warranty reserve is an expense accrual, so the relevant number is the dollars you will spend on parts, field labor, and freight.

How do I model an extended warranty?

Run the calculator at your standard warranty rate, then run it again with the extended warranty claim rate (often higher because more field hours), and add the two reserves.

Does this include hydrogen reimbursement to the customer?

No. If your warranty covers customer downtime or hydrogen reimbursement, fold those costs into the per-claim service cost.

Hydrogen Electrolyzer & Fuel Cell Manufacturing calculator

Stack Warranty Reserve Calculator

Estimate the warranty reserve to book per shipped stack. Enter the number of stacks shipped in the period, the average service cost per claim (replacement parts plus field labor plus return freight), the expected claim rate over the warranty term, and a fixed warranty admin cost. The calculator returns the variable reserve and the loaded total.

What this calculator does

Estimate the warranty reserve booked per shipped stack from stacks shipped, expected service cost per claim (parts plus labor plus return freight), expected claim rate over the warranty term, and a fixed program admin cost.
Use it when a product engineer or finance lead is sizing the warranty reserve for a new PEM, alkaline, SOEC, PEMFC, SOFC, or PAFC stack program before launch and needs a defensible per-stack number.
It returns the warranty reserve to book against shipped stacks, broken into a variable per-stack component and a fixed admin component.

Formula used

Variable warranty reserve = stacks shipped × service cost per claim × expected claim rate
Total warranty reserve = variable reserve + fixed warranty admin cost

Inputs explained

Stacks shipped in the period: Use the count of stacks shipped to customers in the same period the reserve is being booked.
Service cost per warranty claim: Use parts plus field service labor plus return freight per claim, based on prior field settlements (a typical PEMFC stack claim runs in the low thousands; a full SOFC stack swap can be tens of thousands).
Expected claim rate over the warranty term: Use the reliability model or warranty actuarial estimate for the share of shipped stacks that will trigger a claim during the warranty period (typical 1 to 5 percent for mature PEMFC; higher for first-of-kind SOFC or SOEC).
Fixed warranty admin cost: Add fixed admin, registration, recall planning, and case management cost not captured per claim.

How to use the result

Run it during program launch, every quarter the field claim mix changes, or after a known field issue prompts a reliability re-estimate.
It assumes claim cost is roughly normal across stacks. Catastrophic field events (for example a hydrogen leak) need a separate exposure model rather than a per-stack reserve.

Common questions

What claim rate should I assume? Mature PEMFC programs run 1 to 5 percent claim rate over a 5-year warranty. New SOFC, SOEC, or PAFC programs often see 5 to 12 percent in early years until field hours build up.
Should I use list price or cost for claim service cost? Use cost (your spend, not customer price). Warranty reserve is an expense accrual, so the relevant number is the dollars you will spend on parts, field labor, and freight.
How do I model an extended warranty? Run the calculator at your standard warranty rate, then run it again with the extended warranty claim rate (often higher because more field hours), and add the two reserves.
Does this include hydrogen reimbursement to the customer? No. If your warranty covers customer downtime or hydrogen reimbursement, fold those costs into the per-claim service cost.

Last reviewed 2026-05-12.