---
title: "What Is Effective Age? | Calibre Glossary"
description: "Effective age is an opinion representing the difference between a system's expected useful life and its remaining useful life, which may be more or less."
url: https://calibre.multisites.ai/glossary/effective-age
publisher: Calibre Commercial Inspections
phone: "+1-208-305-6245"
email: Schedule@CalibreCBI.com
---

Costs and capital planning

# Effective Age

Effective age is an opinion representing the difference between a system's expected useful life and its remaining useful life, which may be more or less than its actual age.

## Why it matters

Two identical rooftop units can have different effective ages if one was well maintained. ASTM E2018 says effective age varies with maintenance, location and weather. It helps explain why a PCA's replacement timing may not match calendar age.

Source: [store.astm.org](https://store.astm.org/e2018-24.html)

[Related Calibre serviceProperty Condition Assessments](https://calibre.multisites.ai/cre-services/astm-property-condition-assessments)

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