Deep Retrofit and Low Energy Performance of The Existing Building Stock

The threat of climate change has been, and still remains, the key driver for reducing energy consumption in a building sector which accounts for around one-third of global final energy demand[1]. With a projected increase in global energy consumption over the coming decades [2] and an expected increase in energy usage in the building sector [3], both supply level and demand level carbon reductions must be achieved [4]. One of the biggest challenges in the energy efficient retrofit of the existing building stock is the selection of the most appropriate retrofit solution which ensures the best possible annualised thermal comfort performance. In practice, the retrofit of existing buildings has been shown to reduce building energy consumption [5–8] and generally provide enhanced thermal comfort conditions [7,9]. However, the risk of overheating still remains an issue for low energy retrofits [10], as retrofit solutions are constrained by an existing buildings structure.

On 25 October 2012, the EU adopted the Directive 2012/27/EU on energy efficiency in order to achieve the 2020 headline target of 20% improvement in Energy Efficiency [1]. The existing building stock will play a key role in delivering on this target. Buildings in Europe account for 40% of energy consumption [2]. Article 9 of Directive 2010/31/EU “Energy Performance of Buildings (Recast)” requires member states to ensure that all new buildings are nearly zero-energy by 31st December 2020 and new buildings occupied and owned by public authorities are nearly zero-energy after 31st December 2018 [3]. Article 7 states that when buildings undergo major renovation, the energy performance of the building is upgraded in order to meet minimum energy performance requirements set in accordance with Article 4 [3]. However, Article 9 [3] also brings in refurbished buildings under the near zero-energy umbrella by requiring member states to develop policies in order to stimulate the transformation of refurbished buildings into near zero-energy buildings (NZEB). The National Energy Efficiency Action Plan 2009-2020 identified refurbishment of existing public sector buildings as a key area for focus with support for exemplar projects that demonstrate substantial reductions in energy consumption[4]. There is huge potential for non-residential retrofit works as part of the solution in reducing energy consumption in the existing building stock. In 2009 it was estimated that there are 3,083 large public sector buildings over 1,000m2 in Ireland [4]. Furthermore, based on data available from the Irish Central Statistics office, there is potentially over 20,000,000m2 of existing non-residential building stock that was constructed before any national building regulations were in place.

The NBERT initiative aims to support the governments efforts in increasing awareness of the challenges that lie ahead and to provide well documented evidence of energy and environmental performance of a retrofitted low energy building in Cork, Ireland that relies on low energy renewable technologies for heating and power with passive strategies for cooling and ventilation. 

The following section summarises the building concept in the form of a timeline. It provides an overview of the measured energy and environmental performance at the building. It also provides a number of downloadable fact sheets depending on the type of information you are looking for.  

Factsheets