The Act on the Rational Use of Energy, enacted in 2015, establishes the obligation to conform to certain standards for non-residential buildings with a gross floor area of over 300 square meters, the obligation to notify for residential buildings, and the obligation to explain for buildings under 300 square meters. In addition:

• For buildings subject to the obligation to conform, the owner is required to obtain an energy efficiency and conservation conformity assessment by the competent administrative agency or energy efficiency and conservation assessment agency when applying for the required building permit (Article 10).
• If notification is required, the owner must notify the competent administrative agency of the energy conservation plan at least 21 days prior to the start of construction (Article 19).
• If an explanation is required, the architect must explain to the owner whether the building complies with the energy conservation standards and what measures will be taken if it does not (Article 27).

The amended Act on the Rational Use of Energy will come into effect in July 2025. After enactment, all buildings will, in principle, be required to comply with certain specific standards. In particular:

• Buildings that do not comply with the applicable standard will be subject to a correction order, and failure to comply with such an order may result in a fine of up to JPY 3 million (Article 73 of the amended Act on the Rational Use of Energy).
• Different standards and obligations are established for different types of buildings, such as single-family dwellings, large-scale non-residential buildings, and buildings with special structures and equipment.