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Do new houses need mechanical ventilation?

Part F requires adequate ventilation, and any of the recognised systems can be used. In practice, airtight new dwellings usually need a mechanical system — either continuous mechanical extract or mechanical ventilation with heat recovery.

The tighter the building, the less you can rely on background leakage and wall vents to move air. Below a certain airtightness level, natural ventilation strategies become difficult to justify and condensation and indoor air quality problems follow.

Whatever system is chosen, it must be commissioned and balanced, and the homeowner must be given the maintenance information. Uncommissioned MVHR is a common defect.

System options

  • Natural ventilation with background ventilators and intermittent extract
  • Decentralised continuous mechanical extract
  • Centralised continuous mechanical extract
  • Mechanical ventilation with heat recovery

Sources

Last reviewed 28 August 2026. General information only — not legal or planning advice.

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