Home reserve forecast methodology
Version 1.0.0 · ACTIVE · released 2026-06-20
Formula
Seeded Monte Carlo over component lifespan (triangular) + replacement-cost range, inflation-adjusted; per-year P25/P50/P75, cumulative 1/5/10-yr, monthly reserve = P50 cumulative ÷ months.
Default assumptions
| runs | 2000 |
|---|---|
| lifeSpread | {"lowFactor":0.7,"highFactor":1.4} |
| horizonYears | 10 |
| annualInflationPct | 3 |
Not included
- Forecast covers modeled component replacements only — not routine maintenance, upgrades, or remodeling
- Catastrophic events (storm, flood, fire) are out of scope
- Lifespans and costs are modeled distributions, not guarantees
- Replacement costs use a coarse national reference baseline
Change log
1.0.0: initial release. Seeded reproducible Monte Carlo; triangular lifespan + cost; national reference costs.
Reviewed by: methodology. Historical estimates are never overwritten when a methodology changes.