Photo credit: Rockwool UK

A social housing complex in Portsmouth, UK, the original building dating from the 1960s, Wilmcote House comprises three connected apartment blocks of 107 homes whose energy demand after deep energy renovation has been reduced by 90%.

These newly energy renovated apartments meet stringent standards for energy efficiency that are equivalent to passive housing standards (EnerPHiT).  The renovation works took place with residents able to stay in place because of good advance planning.  The results have dramatically improved the living conditions and the quality of life of residents, who feel the positive impacts on their health, well-being and reduced fuel bills.

Portsmouth is the most densely populated city in the UK outside of London and the Somerstown area of the city, in which Wilmcote House is situated, is one of the most deprived areas in England.  Before the energy renovation works took place, residents experienced high heating bills with most of them suffering from serious fuel poverty, mould, damp and condensation that adversely affected residents’ health.


Principal Characteristics of the Renovation Works:

Ownership type: Public body
Year of construction: Circa 1968
Renovation completed: 2018
Floor area after works: 14,500m²
Structure: Original prefabricated, reinforced concrete sandwich panel system was over clad with a continuous airtight ETICS to eliminate thermal bridges.  New triple glazed windows were installed to benefit as much as possible from good energy balance.
Heating and energy: Much of the old inefficient and expensive storage heating was removed and replaced with a mechanical ventilation and heat recovery system as the heating demand was dramatically reduced
Energy performance: Energy savings after works reached 90%
Cost of works: €14.5m (€1,000 per m²)
Architect: ECD Architects Ltd.
Technical consultants: Wilde Carter Clack, NLG and Keegans

Read more about the Wilmcote House renovation project on ROCKWOOL’s website:

ROCKWOOL Report entitled ‘Retrofit to the Rescue: Environmental upgrading of multi-storey estates’: