- 1 - Revision of the C abinet Order, the M inisterial Ordinance  and the 
Notification of the Ministry of Economy, Trade and Industry (METI)  under  
the Act on the Ra tional Use of Energy 
 
October  2019  
Energy Efficiency  Division  
Agency of Natural Resources and Energy  
Ministry of Economy, Trade and Industry  
 
1. Back ground  
 Under the  Act on the Rational Use of Energy  (Law No. 49 of 1979; hereinafter referred to as 
the "Energy Efficiency Law") , the Minister of Economy,  Trade and Industry  (METI Minister) 
shall  establish  and publicise the standards  for manufacturers , processors  and importers with 
regard to improvement of the heat loss prevention performance with respect to  the heat insulation 
building materials  which are specified in the cabinet order under the Energy Efficiency Law  
(hereinafter referred to as " the standards") .  
Additionally, the standards shall  be established by taking account of  the highest level of heat 
loss prevention performance of the respective specifi ed heat insulation building materials  and 
other related factors ( as it is called the " Building Material Top Runner Program") . 
 The METI minister designates  some materials as specified  heat insulation building materials  
and propose s the standards for the  new specified materials to promote the rational ization  of 
energy  use pertaining to heat insulation  building materials  in Japan  in order to cope with the 
recent increase of  energy consumption in the consumer sector , climate change and so forth . 
  The scope of the specifi ed heat insulation building materials  is to be defined in the cabinet 
order for the Energy Eff iciency Law and exceptions  are to be  defined in the ministerial ordinance 
for the Energy Efficiency Law. The standards are stipulated  in the notifications of the METI . 
 
2. Outline of amendment  
    R igid polyurethane foam, which is expected to become widesp read to a considerable extent in 
years to come , is newly  designated as a specifi ed heat insulation building material under 
the " Building Material Top Runner Program" . 
New  standards to be achieved by FY2026 are established for r igid polyurethane foam . 
 
(1) Scope  
  R igid polyurethane foam  which is classified as Class -2 or Class -3 defined by JIS A9521 (2017)  
 
(2) Evaluation index and measuring method of heat loss prevention performanc e  
Thermal conductivity λ [W/(m·K)] is used as the evaluation index for heat l oss prevention 
performance. The thermal conductivity λ [W/(m·K)] is measured by the method defined by 
JISA9521(2017).  
 
(3) Target standard values  (Standard heat loss prevention performanc e) 
・ Class - 2 rigid polyurethane foam defined by JIS A9521(2017) : 0.02216 [W/(m·K)]  
・ Class - 3 rigid polyurethane foam defined by  JISA9521(2017) :0.02289 [W/(m·K)]  
 
(4)Target fiscal year  
    FY2026   
 
- 2 -  
(5)Labeling requirement  
These revisions include requirements  that manufacturers should indicate on their catalog with 
regard to  value of heat loss prevention performance (thermal conductivity λ) etc.  
 
3. Objective  
To promote rationalization of overall energy consumption in Japan through popularisation of 
building materials  with high level of heat  loss prevention performance.  
  
4. Prop osed date of entry into force  
Around spring of 2020