Uniformat D3040

Exhaust fan

Also called EF, roof exhaust fan

• Confidence C
• Version 0.2.0 (permanent link)
• Reviewed 2026-10-22

This is version 0.2.0. The latest is 0.3.0.

Service life

Years in service. The band runs from the shortest to the longest life the sources state, so it shows how much they disagree, not how long 80% of units last. The line is the median of the stated lives.

Basis

• 20 years · CNA e-Tool Estimated Useful Life Table, p12 · HUD CNA 3.4.2.2.12 “Central exhaust fans/blowers” — U.S. Department of Housing and Urban Development (planning life)
  Same life for family and elderly properties. US multifamily housing.
• 20 years · Design standards: employer's requirements – Technical Manual (ER-DFE-XX-XX-T-X-0201, revision A-C01), p256 · 5.6.4 “Air handling units (AHUs), room-based ventilation units, extract fans and controls: 20 years” — Department for Education (England) (design life)
  Printed page 256. AHUs, room-based (heat recovery) ventilation units and extract fans; supply/return fans in AHUs included. Minimum life expectancy (design requirement) for DfE-funded school buildings. Minimum design requirements placed on contractors for school buildings, not observed replacement ages. Section 5.1.4 (sanitaryware) refers to CIBSE Guide M Appendix 12.A1 'in general'.
• 15 years · Energy Conservation Program: Energy Conservation Standards for Fans and Blowers (notice of proposed rulemaking), 89 FR 3714, January 19, 2024, p75 · IV.F.6 “Equipment Lifetime: GFBs, "15 years in the commercial sector based on the expected lifetimes of HVAC equipment"” — U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (planning life)
  Printed page 3788. Commercial-sector lifetime for general fans and blowers (all fan types). Proposed rule; the 15 years is borrowed from HVAC equipment lifetimes, not fan data.
• 10 years · General depreciation rates (IR265), July 2021, p44 · BDFO “Ventilating fans” — Inland Revenue (Te Tari Taake), New Zealand (accounting life)
  Printed page 44. Ventilating fans, not ducted or roof-mounted (e.g. wall or window fans). BDFO Building fit-out (when in books separately from building cost). Printed DV 20%, SL 13.5%. Tax depreciation lives set by the Commissioner of Inland Revenue for New Zealand income tax, not engineering or asset-management lives; they are banded and often short (e.g. reticulation piping 25 years). The July 2021 edition was the newest PDF reachable; the online Depreciation Rate Finder may hold later determinations.
• 15.5 years · General depreciation rates (IR265), July 2021, p44 · BDFO “Ventilating fans (ducted)” — Inland Revenue (Te Tari Taake), New Zealand (accounting life)
  Printed page 44. Ducted ventilating fans, supply or exhaust. BDFO Building fit-out (when in books separately from building cost). Printed DV 13%, SL 8.5%. Tax depreciation lives set by the Commissioner of Inland Revenue for New Zealand income tax, not engineering or asset-management lives; they are banded and often short (e.g. reticulation piping 25 years). The July 2021 edition was the newest PDF reachable; the online Depreciation Rate Finder may hold later determinations.
• 15.5 years · General depreciation rates (IR265), July 2021, p44 · BDFO “Ventilating fans (roof mounted)” — Inland Revenue (Te Tari Taake), New Zealand (accounting life)
  Printed page 44. Roof-mounted ventilating fans. BDFO Building fit-out (when in books separately from building cost). Printed DV 13%, SL 8.5%. Tax depreciation lives set by the Commissioner of Inland Revenue for New Zealand income tax, not engineering or asset-management lives; they are banded and often short (e.g. reticulation piping 25 years). The July 2021 edition was the newest PDF reachable; the online Depreciation Rate Finder may hold later determinations.
• 20 years · Future Buildings Standard: final stage impact assessment (RPC-MHCLG-25104-IA), 24 March 2026, p77 · Appendix B “"20 years for light fittings and ventilation equipment"” — Ministry of Housing, Communities and Local Government (UK) (planning life)
  Printed page 77. One value for two groups. Light fittings in new buildings are LED (the IA applies LED cost learning). 'Ventilation equipment' is generic; mapped to the ventilation component types it clearly includes. Assumption for new non-domestic buildings in England; the IA says the lifetimes are in line with BS EN 15459 (Annex/Appendix E), but they are stated as the department's own modelling assumptions, not a reproduced table. Round-number economic-appraisal assumptions, not observed lives. Same values as the January 2021 Future Buildings Standard consultation IA (separate file), so the two are not independent.

How sources are chosen and recorded: sourcing policy.

Preventive maintenance

8 tasks in 3 work orders. Intervals that fall due together are one visit: the annual visit also covers the monthly tasks.

1. 1Monthly
2. 2Monthly
3. 3Monthly
4. 4Monthly
5. 5Monthly
6. 6Monthly
7. 7Monthly
8. 8Monthly
9. 9Monthly
10. 10Monthly
11. 11Monthly
12. 12Annual

Months from the schedule start. Daily and weekly rounds run in between. Download the tasks as CSV for a CMMS, or ask the MCP tool get_pm_schedule for dated visits.

Frequencies are ISO 8601 durations in the data (P3M = every 3 months).

Open questions

• Every source here is a published planning, design or accounting life. None is observed replacement data.

Know the answer? Send it with a source to [email protected].

Cite this

Citation

unfinished.one (2026). Exhaust fan, v0.2.0. https://unfinished.one/c/exhaust-fan/v/0.2.0

BibTeX

@misc{unfinished_exhaust_fan_0_2_0,
  title = {Exhaust fan},
  author = {{unfinished.one}},
  year = {2026},
  version = {0.2.0},
  url = {https://unfinished.one/c/exhaust-fan/v/0.2.0},
  note = {CC BY 4.0}
}

Licence CC BY 4.0 · How to cite · JSON · Versions: 0.3.0, 0.2.0, 0.1.0