The rising cost to heat homes this chilly winter raises the question of whether or not one's dwelling is well insulated against the elements. Masatoshi Takeuchi, an architect and professor at Tohoku University of Art and Design in Yamagata answers this question.
"Among the G7 countries, Japan is the only one not imposing insulation requirements on housing construction," he tells Weekly Playboy (Feb 13). "In Asia, even South Korea and China have insulation requirements."
"Many economically advanced nations , as part of their global warming measures, are constructing housing with outstanding energy-saving and carbon-free properties," Takeuchi continues. "But Japan is way behind. It is still stuck in the energy-saving policies adopted in 1999. Which are not even mandatory. And even the insulation that clear standards suffer in comparison to countries like Germany. For a dwelling in Japan having 100 square meters, the volume of kerosene required for heating over one year is seven times that of Germany. And the majority of existing homes in Japan don't even clear the country's own standards."
In fact, points out Takeuchi, fewer than than 70% of Japanese homes conform to to the insulation standards that were applied from 1980.
Takeuchi identifies two main reasons for Japan's poor showing. "The first is the preconceived notion that Japan is a warm country... so standards have been established with this in mind. But Japan no longer has the temperate four-season climate it once did. Summers in particular are getting harsher every year, making air conditioning a necessity. In the past, a well-ventilated house was considered ideal, but nowadays you don't want to live in such a house, because at 40° C, any breeze you feel will just be hot wind.
"The climate is changing, but the standard of house construction has not changed," he said.
The second reason is attributed to misguided views relating to housing and the economy, driven by the widespread belief that the total number of housing starts is tied to economic performance, i.e., when the economy is strong, more houses are built, and vice-versa.
"Therefore, when talk of establishing a new construction standard comes up, some people are wont to object, saying, 'Won't that hurt the economy?'" Takeuchi said. "In fact, the cabinet once did approve of implementation of mandatory standards for insulation by 2020, but the Ministry of Land, Infrastructure, Transport and Tourism strongly opposed it, claiming it would affect small- and medium-sized home builders, who 'lack experience.' The ministry's view was that if the standard were implemented, the number of construction starts would decrease, hurting economic growth."
As things currently stand, compulsory insulation requirements won't go into effect until 2025. Nevertheless, builders are installing insulation proactively and Takeuchi estimates that about 85% of single-unit houses and 70% of apartments currently being built will meet the new standards.
When the mandatory insulation standards are finally adopted, owners of existing structures are likely to become eligible for home-improvement subsidies.
Raising the quality of insulation will require 10-cm-thick glasswool insulation panels for walls and 20cm-thick panels for ceilings. Another measure is installation of double-glazed windows, with aluminum exterior and uPVC inner sashes. (Sashes composed 100% uPVC afford even better insulation, but at higher cost.)
Affordable measures like insulation-type window blinds are also readily available.
"The blinds are like wearing a down jacket, which traps heat between the body and the jacket," Takeuchi tells Weekly Playboy, adding, "Condo residents may be able to improve insulation without extensive renovations by installing a new type of inner sash. Tenants might want to discuss the matter with their landlords and offer to share the costs for installation. Chances are they'll get a favorable response."© Japan Today