What a ventilation audit covers
A ventilation audit measures actual air-change rates across a dwelling and assesses whether existing or proposed ventilation provision matches Building Regulations Part F and the dwelling's occupancy. The audit is essential before insulation work (existing ventilation may become inadequate) and after (to verify the upgrade is performing as designed).
- Visual inspection of all background ventilators, MVHR / MEV / dMEV systems where present
- Air-leakage testing (blower-door) where commissioned
- Room-by-room air-change-rate measurement
- Filter and duct condition inspection
- Commissioning verification against design intent
- Recommendations against Part F current standards
Typical findings
- MVHR systems running at 30-50% of design flow due to commissioning failures
- Background ventilators blocked, painted over, or removed
- Extract fans below required flow rates
- Post-insulation properties with insufficient ventilation provision
- Rooms (especially bathrooms) without adequate purge ventilation
Typical cost: £250-£500 visual ventilation audit, £500-£1,200 with measurement and commissioning verification, £600-£1,400 with blower-door test
When to book: Before any insulation or airtightness work, after any insulation work, when condensation or mould patterns suggest under-ventilation, or when MVHR is suspected of underperforming.
Required qualifications for assessor: BPEC ventilation qualification (Domestic Ventilation Installers, Domestic Ventilation Inspector), or BSRIA-trained commissioning engineer for MVHR work