日本の住宅の変遷に伴う断熱性能の変化と冷暖房負荷に関する研究

学生名：外尾　隆也

研究テーマ：日本の住宅の変遷に伴う断熱性能の変化と冷暖房負荷に関する研究

入学年月:2018.04

修了年月:2020.03

取得学位:修士（工学）

論文概要:In recent years, Japan has faced challenges related to its stock-type society, characterized by a growing surplus of underutilized housing. As of 2008, 7.57 million vacant houses existed, with 27.5% built before 1981. Many of these older houses do not meet modern energy-saving standards, necessitating research into their insulation performance and potential for renovation. This study analyzes changes in Japanese housing, focusing on insulation performance and air-conditioning load. Kyoto, where traditional Machiya houses are prevalent, was selected as the research area. Three house models were examined: Machiya, medium corridor houses, and narrow houses. Energy performance was assessed during cooling periods (July–September, with a set temperature of 28°C) and heating periods (December–March, with a set temperature of 20°C).

The analysis reveals that changes in housing design over time have negatively impacted insulation performance. Transitioning from Machiya to corridor-type and from medium-corridor to narrow houses leads to reduced insulation, resulting in increased energy demands for heating and cooling. To evaluate whether these traditional housing stocks can meet modern standards, the study established an energy-saving standard of 58.65 kWh/m² based on comparisons between current housing models and modern energy-efficient designs.

Findings indicate that only narrow houses with both wall and window insulation can meet the proposed energy-saving standard. For Machiya and medium corridor-type houses, normal insulation repairs are insufficient to meet modern standards. Large-scale insulation upgrades are required for these house types to align with contemporary energy efficiency requirements. Narrow houses, on the other hand, can be adapted for modern use with standard insulation measures.

This study highlights the need for significant insulation improvements in traditional Japanese housing stock to meet modern energy-saving standards. While narrow houses can be relatively easily adapted, older Machiya and medium corridor houses require extensive renovations to remain viable in contemporary society.