Case Studies

Putting the OPW approach into practice, six energy upgrade case studies have been developed to date. The buildings were chosen as they are representative of common traditional building typologies in Ireland and across Europe, but they also provide valuable learnings from the unique complexities and variances in construction, use and historic characteristics and they present.

Each case study is informed by an in-depth understanding of the construction and actual condition of each building using on-site testing, such as in-situ U-value tests, moisture absorption tests, thermal imaging and airtightness tests. Designs were guided by an experienced Conservation Architect and a Heritage Impact Assessment was completed at the project outset to guide the overall upgrade strategy for the building. This was continually revisited throughout the design process as different upgrade options were considered. In all instances, the primary objective was to preserve the heritage of the buildings whilst improving its energy efficiency in a safe and appropriate manner.

A whole life cycle approach was taken and insulation materials were reviewed against their associated global warming potential using Environmental Product Declarations. Although the reuse of existing buildings generally leads to generous savings in embodied carbon compared to a new build projects, other life cycle assessment studies have shown that renovations can be surprisingly carbon intensive if the embodied carbon of renovation materials is not considered from the outset of the design process.

Fabric upgrade proposals were then tested in specialist software to assess potential hygrothermal risks. These risk assessments focused on the junctions rather than planar elements as this is where the risk of condensation and thermal bridging is highest.

Five of the six case studies were desk-based, however the energy upgrade of the Block M Offices at Dublin Castle is complete. This is now functioning as a ‘live laboratory’ where the OPW are monitoring the long-term surface and interstitial temperature and moisture levels of two types of internal solid wall insulation. The findings from this ongoing in-situ monitoring will be used to inform future upgrade works to other buildings.