Study on insulation retrofitting based on thermal environment and the CASBEE health checklist evaluation

Abstract

The Carbon Neutral Declaration has been issued in Japan and various initiatives are introducing to realise it, but in the housing sector it is essential to improve the energy efficiency of the stock of over 50 million homes. However, the progress of insulation retrofitting is slow. In particular, there are many challenges in implementing insulation retrofitting in condominiums, including the requirements of residents consent. This study aims to clarify that thermal environment data and the Comprehensive Assessment System for Built Environment Efficiency (CASBEE) health checklist for motivating thermal insulation retrofitting and to support the effectiveness of this approach. The thermal environment data compares energy consumption and room temperature before and after the retrofit and quantifies the effect of the retrofit. The CASBEE health checklist displays health characteristics and health rankings for each room and health factor by answering 50 questions about the indoor environment in winter. These are considered to visualise the effects of the renovation of respondents' homes and enable them to realise the need for renovation. This method was applied to Ta housing complex in Kanagawa prefecture and X housing complex in Tokyo, where insulation retrofitting had already been carried out, and an attempt was made to verify the effectiveness of the method by comparing the environmental improvements resulting from insulation retrofitting and the differences in residents' responses. The results of the Ta complex showed that the room temperature was 20°C in the living room and 18°C or higher in the entrance hall, indicating that good environment had been achieved; the CASBEE health checklist also showed an improvement in health characteristics and health ranking in both the Ta and X complexes. The results suggest that the effects of retrofitting in terms of both physical and psychological health are significant. In the future, the results will be presented to the management associations of non-retrofitted dwellings and, in combination with experience sessions in retrofitted dwellings, will be verified as an effective motivational tool.