Comparative building performance evaluation of a ‘sustainable’ community centre and a public library building

This paper uses a forensic building performance evaluation approach to undertake a comparative evaluation of the in-use energy and environmental performance data (collected over two years) of two civic buildings located in Southeast England – a small community centre (<1000 m²) and a medium-sized public library building (∼4500 m²), which are designed to high sustainability standards (EPC A rating) and low heating demand met by on-site low/zero carbon technologies. Although both buildings achieved measured air-permeability rates of ∼5 m³/h.m², they encountered similar issues related to poor documentation of ‘as-built’ drawings, poor handover and guidance, problems with integrating and maintaining new technologies (heat pumps, biomass boilers and solar thermal), lack of calibration of sub-meters, and issues with automatic window controls. However, the actual annual energy use of the community centre is similar to the design prediction, while it is almost double the prediction in the case of the library building. This is because the community centre management team overcame some of the issues through their continuous engagement and interest in the building’s performance, whereas the management team of the Library building failed to engage with energy management, resulting in disuse of the biomass boiler and solar thermal system.

Practical application : Comparative building performance evaluation (BPE) systematically reveals the similarities and differences in the actual energy and environmental performance of two ‘sustainable’ civic buildings. Careful management of heating and electricity loads, good occupant control over the indoor environment and high performance of low-carbon technologies in the Community Centre results in the building performing better than good practice benchmark. Regular changes in facility management (FM) staff result in inadequate energy management and control over heating, ventilation and lighting, that undermines occupant comfort and leads to excessive energy use in the library building. For civic buildings to perform as designed, it is vital that metering, sub-metering and controls are set up, commissioned and used properly by the FM team. Design teams should ensure that easy-to-understand user guides are made available before handover for FM and occupants.