Passivhaus Affiliate

Encraft trial OWLS whole building retrofit solution

Passivhaus Trust Patron members Encraft are trialling a whole building retrofit solution in a project known as OWLS (Off-Site Wrap-Around Large Scale Retrofit), after receiving funding from the Innovate UK Scaling up Retrofit competition.






Over 30% of all households in the social housing sector are unable to heat their houses satisfactorily, due to people being unable to afford their bills or their heating systems being insufficient to properly heat their homes. Current options for retrofit to reduce energy demands are often limited by high cost, and replacing heating systems alone may only achieve a moderate reduction in energy bills. Alterations to the building fabric are necessary in order to not only reduce energy demand but also to significantly lower maintenance costs.

Last month [September 2015], work began on the deep retrofit of Grandy’s Croft in Solihull. Encraft and their project partners have developed a system that will include a complete new façade and roof, new high-performance windows and doors and MVHR using Beattie Passive’s TCosy™ retrofit system. The retrofit is predicted to achieve up to 85% savings on heating bills on a block of low rise flats and is aiming for EnerPHit certification.

Grandy's Croft, Solihull. Image credit - Encraft

This deep retrofit solution will act as a prototype to potentially be applied to all property types which are well suited to external wall insulation (EWI). It will also address associated properties that require roof insulation, glazing and draught proofing. The system is envisaged to be most cost-effective in properties that require a package of these energy saving measures and in non-traditional and system builds that may require specialist treatment and are often categorised as ‘hard-to-treat’.

The key aim of the project is to prove the success of this kind of approach in order that it can be taken forward to market in a large scale roll out.

Matthew Rhodes of Encraft and Ron Beattie, Beattie Passive will be discussing the project at the upcoming UK Passivhaus Conference 2015. Click to see the programme and buy your conference tickets. Keep updated with #UKPHC15.

Key team

Project Management: Building Physics team at Encraft

Contractor: Beattie Passive

Owner: Solihull Metropolitan Borough Council

Client: Solihull Community Housing

Occupancy skills programme & monitoring: Coventry University



Further information

6th October 2015

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