Japan Solar Update: No.158 (Juy 21 ~ 25, 2025)
<Key points>
- The Ministry of Economy, Trade and Industry (METI) has proposed a revision to the definition of ZEH (Net Zero Energy Houses), requiring the installation of storage batteries in detached houses equipped with PV systems
- To encourage a higher PV installation rate per household, METI plans to introduce higher-grade categories such as the New ZEH+
- The new definition is scheduled to be applied to new certifications starting in FY 2027, and public comments are being solicited
Review of ZEH definition
Concept of the review of definition
- For detached houses, the installation of equipment that contributes to self-consumption is required
- Higher-grade categories are to be introduced with the aim of promoting an increase in the PV installation ratio per household
Definition of New ZEH (draft)
| Detached houses | Detached houses | Collective housing | |
| Energy-saving performance | Heat insulation performance | Heat insulation grade: 6 | Heat insulation grade: 6 |
| Rate of reduction in primary energy consumption (only energy-saving included) | 35% | 35% | |
| Requirements for equipment *1 |
1. High level energy management 2. Storage batteries |
– | |
| Regional characteristics and building characteristics *2 (Criteria for ZEH-Oriented, which does not require installation of renewable energy systems) |
・Snowy region ・Small land in urban areas |
・Snowy region ・6th floor and above |
|
| Requirements for renewable energy (Rate of reduction in primary energy consumption including renewable energy) |
New ZEH+: 115% New ZEH: 100% Nearly New ZEH: 75% |
New ZEH-M+: 115% New ZEH-M: 100% Nearly New ZEH-M: 75% New ZEH-M Ready: 50% |
|
*1: EV chargers/dischargers are designated as recommended equipment, and architects are required to provide explanations of the necessary information when considering installation
*2: Renewable energy equipment is designated as a recommended measure, and architects are required to provide explanations of the necessary information when considering installation
*3: Applicable only when PV systems are installed
Upcoming schedule (draft):
・The new definition will be applied to new certifications starting in FY 2027. Under the current definition, new certifications are scheduled to be discontinued, due in the end of FY 2027
・However, in cases where houses built by FY 2027 are renovated, certification under the current definition will still be allowed
Public comments are now being solicited on the proposed revision of the definitions for ZEH and ZEHM (for detached houses and collective housing)
Public comments are solicited between May 28 and June 27, 2025
Figure 1 Review of the definition of ZEH and upcoming schedule, etc.
Source: Materials of the 48th meeting of the Energy Efficiency and Conservation Subcommittee (May 12, 2025), compiled by RTS Corporation