When you spend on flood-proofing, the real question is simple: will it pay for itself? Enter your expected risk (or let the tool estimate it), your upgrade cost, any premium changes, and maintenance. You’ll get clear results, annual savings, simple payback, NPV, IRR, and a year-by-year cash-flow table, so you can decide with confidence.
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Will This Upgrade Pay Off?
Flood-proofing savings & payback calculator
NPV
IRR
Benefit–Cost Ratio
Simple Payback
Choose a starting point—values auto-fill. Adjust anything to match your home.
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Costs & incentives
Net upfront = Upfront − Rebate. We discount future cash flows at your chosen rate.
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Flood risk & damage
Annual Expected Loss (AEL) = probability × (damage + downtime). The upgrade can lower both.
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Results
Annual savings (est.)
$0
Baseline AEL − Post-upgrade AEL + insurance savings − maintenance
Simple payback
—
Net upfront ÷ annual savings
Benefit–cost ratio
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PV of benefits ÷ PV of costs
NPV (at discount rate)
$0
PV(benefits − costs) over horizon
IRR (estimated)
—
Rate where NPV ≈ 0
Baseline vs. Post AEL
$0 → $0
Annual Expected Loss comparison
Tip: Adjust any field—results update on Calculate.
What the numbers mean
Annual Expected Loss (AEL) is the long-run average loss per year from flooding or sewer backup.
Annual savings = (Baseline AEL − Post-upgrade AEL) + Insurance premium reduction − Maintenance.
Simple payback ignores discounting; it’s years to recover the net upfront cost.
NPV discounts future savings at your chosen rate over the analysis horizon (with residual value at end).
IRR is the discount rate that makes NPV ≈ 0 (uses a bisection search—robust for typical home projects).
Benefit–Cost Ratio compares the present value of benefits to costs; > 1.0 means benefits exceed costs.