ESTIMATION OF EFFECT OF INJECTING POLYURETHANE FOAM INTO WALLS AND RENOVATING WINDOWS IN HOUSES IN JAPAN UP TO 2020 STUDY ON REDUCTION OF GREENHOUSE GASES FROM RENOVATING THERMAL INSULATION IN HOUSES

This research describes the effects of injecting rigid polyurethane foam into walls and fitting doubleglazing or inner panes to sash windows as simple renovation methods for houses, based onestimations of CO2 emissions from heating/cooling and LCCO2 (Life Cycle CO2). We estimated CO2emissions and LCCO2 up to 2020 in Japan and obtained the following results.(1) Injecting rigid polyurethane foam into walls in detached houses, where there is little thermalinsulation, reduces the LCCO2 significantly. (2) In regions with mild climates like Tokyo, renovatingwindows brings higher LCCO2 reductions in houses insulated to 1992 Criteria for the Rational Use ofEnergy in Houses1) than in those insulated to conventional levels or the 1980 criteria. (3) Whenchoosing one of the two methods above, we should take into account the initial insulation level, thehouse structure, and the region. (4) Domestic CO2 emissions for houses in Japan can be reduced by13% to 19% by 2020 with the use of simple renovation methods for thermal insulation.