 
Revisions of Enforcement Ordinance , Regulation  and the Notification of the Ministry of 
Economy, Trade and Industry (METI) under the Act on the Rational Use of Energy  
 
April  2022 
Energy Efficiency Division  
Agency of Natural Resources and Energy  
Ministry of Economy, Trade and Industry  
 
1. Background  
Under Article 150 of the Act on the Rational Use of Energy (Law No. 49 of 1979; 
hereinafter referred to as "Energy Efficiency Law"), the Minister of Economy, Trade and 
Industry shall establish and publicise standards  of judgment for manufacturers, processors 
and importers with regard to the improvement of the performance for the specified 
prevention of heat loss from envelopes of houses and/or buildings. It is prescribed in the 
Energy Efficiency Law that new performance standards for prevention of heat loss from 
envelopes o f houses and/or buildings shall be established taking account of the 
performance of the building materials which show the highest heat insulation performance  
amongst the respective specified insulation materials  and other related factors. (It is called 
the "Building Material Top Runner Program".)  
The scope of the specified insulation materials and exceptions are to be defined in  the 
Enforcement Ordinance  and Regulation for the Energy Efficiency Law.  The performance 
standards are stipulated in the “Notifications of the Ministry of Economy, Trade and 
Industry”.  
 
2. Outline of Development  
The principal  points of development are as follows:  
 i)  Target standard values  
Category  Current target  
standard value  
[W/(m2･K)] Next target  
standard value  
[W/(m2･K)] 
Sash  Sliding  3.50 2.16 
Vertical 
Casement  3.75 2.06 
Horizontal 
Casement  3.69 2.04 
Fixed  3.35 1.87 
Double -hung  3.97 2.30 
Glazing  2.19 1.67 
 ii)   Target fiscal year  
Category  Current target  fiscal year  Next target fiscal year  
Sash  FY2022  FY2030  
Glazing  FY2022  FY2030  
 
iii)  Exception s from sash and glazing  
Material of s ash Current scope of 
exceptions  Iron or wooden sash  
Next scope of 
exceptions  Iron sash  
Total thickness  
of glazing  Current scope of 
exceptions  Over 10mm  
Next scope of 
exceptions  Over 10mm （limited to each thickness is over 5mm ） 
 
3. Objective  
To promote rationalization of overall energy consumption in Japan through popularisation 
of building materials  with high heat insulation performance.  
 
4. Proposed date of entry into force  
Around April  of 202 3*  
*Target fiscal year for achieving the new standard is set to be FY20 30. 