ZEB is an abbreviation of the Net Zero Energy Building, and its purpose is to promote the use of renewable energy on the condition of realizing both comfortable indoor environment and super-energy saving. In a quantitative way, buildings achieving 50% or higher energy saving are defined as ZEB Ready, buildings achieving net 75% or higher energy saving, including utilization of renewable energy, are defined as Nearly ZEB, and buildings achieving 100% or higher energy saving are defined as ZEB. Moreover, ZEB Oriented, with judgment criteria that can be easily used even for large-sized buildings, has also been newly established. In fiscal 2025, we have set a goal of ZEB accounting for 50% or more of our order design work.

<PDF>BELS Evaluation Document

Daiho’s Institute of Technology, which was completed in 2020, was designed with the aim of obtaining ZEB and achieved the reduction rate 54% from the standard primary energy consumption and successfully obtained ZEB Ready.

When calculating annual costs, power consumption of the building is considered to be the same as the secondary energy consumption. Secondary energy consumption (MWh) = Primary energy consumption (GJ) / 9760 (KJ/kWh) ×1000 This simulation is the comparison where the building was used for eight hours 250 days a year. Moreover, electric charge is assumed to be 17 yen per 1 kWh. The resulting annual charge is 1,937,830 yen based on the calculation from standard primary energy consumption, and 957,610 yen based on the calculation from designed primary energy consumption, which results in annual savings of 980,220 yen.

Although initial costs are high, adoption of ZEB has a variety of advantages, in addition to reducing energy consumption. Building stakeholders include its owner, workers, visitors, and other people in various positions, and ZEB is beneficial to everyone, though in different ways. Therefore, in order to realize and disseminate ZEB, we think it is important to carefully explain its advantages to ask for their cooperation.