Effectiveness of low-cost non-invasive solutions for daylight and electric lighting integration to improve energy efficiency in historical buildings

Abstract

This article concerns a field study about the use of non-invasive manual lighting and shading control to save energy in listed buildings. The system was chosen to limit cabling and masonry work. The test room consists of an individual office located in a historical building in Southern Italy. The room was retrofitted with two roller shades (semi-transparent and blackout) and six LED-based pendants provided with step-dimming and three Correlated Colour Temperature options. Shading and lighting could be remotely controlled from the desk by six subjects who took part in the test for two weeks each. Behavioural interventions and a set back to default setting at the end of the working day were adopted to improve the test subjects’ energy behaviour. The results show that energy for lighting could be reduced between 15% and 71% compared to European benchmark, with wide range accounting for variability of individual preference and weather conditions. The savings are due to the computer-based work, the communication and engagement campaign, as well as the default settings. The findings suggest that simple manually controlled systems are energy and economic viable solution for listed buildings, since the system accommodates users’ needs, and proper training is provided to the users.