Key learnings

• These sort of wall compositions need to viewed as one system and require good buildable junction details. Brickwork contractors needed to be supported.
• Where it was used (to reduce air permeability) the polymer spray was accomplished successfully, but no one else can work in the house at the same time.
• The quality control of the fabric needs to be recognised within contracts that reflect the difficulties of wall composition.
• Glazing decisions are not purely based on performance, but also on weight, availability, security and maintenance,
• The M&E contractors were unfamiliar with some of the systems and needed valuable support from the heat pump manufacturers. The M&E contractor subcontracted the PV system which led to disconnects and the need for further co-ordination. Finding space in existing house layouts for hot water cylinders can be challenging.
• When installed the MVHR unit was placed in the loft and the duct work ran through the I-joists.
• Heat pump location, security and the installation of insulation/protection to pipework needs careful consideration. Common presentation of installation across manufacturers would be aid understanding and roll-out. Effective commissioning and on-going maintenance are essential. Contracts need to encourage meeting design performance.
• Controls need to be more user friendly. Handover must be carefully managed. Occupants need more information.
• Ventilation systems need to have a test certificate.
• Ventilation pathways, especially under doors need to be maintained (e.g. when fitting floors).
• Occupants need to understand their roll in achieving healthy air.