PIV units for damp & mould compliance.

Awaab’s Law — the implied tenancy term in section 10A of the Landlord and Tenant Act 1985, inserted by section 42 of the Social Housing (Regulation) Act 2023 and given effect by the Hazards in Social Housing (Prescribed Requirements) (England) Regulations 2025 (SI 2025/1042) — came into force for the social rented sector on 27 October 2025. Under this framework, registered providers of social housing must respond to hazards within five statutory deadlines, structured across two tracks.

For emergency hazards, landlords have 24 hours from awareness to investigate AND make safe— the obligation runs in calendar hours, including weekends and bank holidays.

For significant hazards (which include all damp and mould hazards within the Phase 1 scope), four further deadlines apply: 10 working days to investigate; 3 working days to provide a written summary of the findings of the investigation (Reg 9 of SI 2025/1042); 5 working days to complete safety works; and a 12-week (84 calendar day) backstop measured from the day after the investigation is completed (Reg 13(3)(b)) by which any additional preventative works must begin at the latest.

Phase 1 (in force since 27 October 2025) covers two categories: damp and mould as significant hazards, and all emergency hazards across all HHSRS hazard categories — including dangerous electrical faults, major leaks, severe penetrating damp, and water leaks causing electrical safety risks. Phase 2 in 2026 will extend the significant-hazard track to excess cold and heat, falls, structural collapse and explosions, fire and electrical hazards, and domestic and personal hygiene and food safety.

The Renters’ Rights Act 2025 (Royal Assent 27 October 2025) is also relevant. Since 1 May 2026, the maximum civil penalty for failure to comply with an Improvement Notice (under section 249A of the Housing Act 2004 and section 23 of the Housing and Planning Act 2016) has risen from £30,000 to £40,000. The Act also contains provisions to extend Awaab’s Law to the private rented sector, expected to come into force during Phase 3 of the Act in 2027. Installing effective ventilation now is a cost-effective way to get ahead of the regulatory direction of travel for both social and private landlords.

PIV directly addresses the most common cause of residential mould: excess moisture from cooking, showering, drying clothes, and breathing. By maintaining a constant airflow, PIV prevents moisture from settling on cold surfaces. It is one of the most practical interventions a landlord can install — particularly in pre-2000 housing stock that was not designed with modern ventilation standards in mind.

PIVsuits older properties with natural air leakage, properties suffering general condensation across multiple rooms, and any situation where a whole-house solution is needed at relatively low cost. It covers most pre-2000 UK housing stock — the bulk of rental properties.

Mechanical extract fans(bathroom extractors, continuous mechanical extract ventilation / cMEV) belong in wet rooms — bathrooms, kitchens, utility rooms — where moisture is concentrated. Building Regulations Approved Document F requires extract ventilation in these rooms as a minimum. Treat extract as complementary to PIV, not a replacement.

MVHRsystems — supply and extract through a heat-exchanger ducted network — suit airtight new-build properties designed to Part L standards. They are typically £3,000–£7,000 installed and impractical to retrofit into most existing rentals. For older housing stock, PIV is the practical choice.

In many cases, the optimal landlord strategy is a PIV unit in the central hallway combined with intermittent extract fans in wet rooms.