LCA for a Well-Insulated and Airtight House for Two-Generation Family in Whole House with Continuous Heating and Cooling —Part 1: Comparison of LCCO₂ Levels in One House in Terms of Insulation Specifications—

Abstract

Objective and Method. We compared the heating and cooling energy consumption of a house with good insulation and then with more insulation. Our target house was a well-insulated and airtight house in Nagano City. We targeted the energy saving standards of 1980, 1992, 1999, the HEAT20 G1, and the HEAT20 G2. We compared the life cycle CO₂（LCCO₂） emissions from the house with good insulation and then with more insulation in a cold district for 30 years.

Results. A house built by HEAT20 G2 standard has more CO₂ emissions until two years after construction than that by the energy saving standard of 1999. A house built by the energy saving standard of 1999 has 2.8% more CO₂ emissions than that of the HEAT20 G1 standard, and 4.5% more than that of the HEAT20 G2 standard.

Conclusions. We clarified that the CO₂ emissions from the house with more insulation was higher than that of the house with less insulation during construction. However, the CO₂ emissions from the house with more insulation was less than that of the house with less insulation from cradle to grave.