Aiming to be a platform for co-creating social and environmental design
Construction Begins on New Hokkaido Office Building
First building in Hokkaido to achieve “Nearly ZEB” status through energy conservation alone

Nikken Sekkei Ltd. (Headquarters: Chiyoda Ward, Tokyo; President and CEO: Atsushi Omatsu; hereinafter “Nikken Sekkei”) began construction of its new Hokkaido office building on October 1, 2024, and held a groundbreaking ceremony on October 2. Completion is scheduled for November 2025.

In Hokkaido, where abundant nature and urban areas coexist, cutting-edge initiatives have been underway in recent years—such as the development of renewable energy, the promotion of the space industry, and the pursuit of well-being—that leverage the region’s strengths, demonstrating its high potential for realizing a sustainable society.
Against this backdrop, Nikken Sekkei merged with its group company, Hokkaido Nikken Sekkei, in April 2022 to further accelerate its activities in Hokkaido. Today, challenges related to architecture, urban planning, and the social environment are becoming increasingly complex and cannot be solved by a single company alone.The new headquarters aims to serve as a hub for designing the social environment of the future, addressing contemporary themes such as the realization of ZEB in cold, snowy regions, DE&I, wellness, and wood-based construction, while also serving as a platform for co-creation that brings together diverse expertise from both within and outside the company.

On September 19, 2024, we obtained “Nearly ZEB” certification under the Building-Housing Energy-efficiency Labeling System (BELS), indicating a reduction of at least 75 percent from the standard primary energy consumption.
Our new headquarters achieved a 75% reduction through energy conservation alone; when combined with energy generated by solar power, the reduction reaches 87%. This marks the first time a building in Hokkaido has achieved “Nearly ZEB” status through energy conservation alone.

To achieve a decarbonized society, there is a growing need to transform buildings—including office buildings—into Zero Energy Buildings (ZEBs). In Hokkaido, in particular, “decarbonization” has been newly added to the list of roles the prefecture must play in addressing national challenges; furthermore, Sapporo City is advancing the development of renewable energy and the decarbonization of its urban areas as part of its goal to become the “Environmental Capital: SAPPORO.”
In Hokkaido, the high energy consumption associated with heating presents a major hurdle to making buildings ZEBs. This is considered a key issue that requires attention for decarbonization efforts in all cold, snowy regions.In designing this office, we are actively incorporating energy-saving concepts unique to cold regions: opening up to the outside in summer to take advantage of the cool climate, and closing off the interior in winter to minimize heat loss.

In order to achieve “Nearly ZEB” status, we reevaluated the performance requirements for our own offices based on operational data from our existing facilities. Building on that, we combined measures to ensure thermal insulation, natural ventilation, and natural lighting with the use of renewable energy and high-efficiency HVAC and lighting systems.
Construction of the Hokkaido office is scheduled for completion in November 2025, but even after completion, we will continue working toward achieving ZEB status through energy-saving operational practices and expanded use of renewable energy.

① Reducing Heating and Cooling Loads by Utilizing an Inner Terrace (Buffer Zone + Natural Ventilation)
The glass inner terrace, which opens onto the green space on the west side, promotes natural ventilation in the office spaces through the chimney effect of the ventilation tower, thereby reducing the cooling load. Furthermore, by drawing in cool outside air at night to cool the building, it reduces the initial cooling load.During the cold winter months, it functions as a buffer zone that acts like a glass greenhouse to store solar heat, thereby reducing the heating load.

② Utilizing Well Water Heat and Geothermal Heat to Improve Heating and Cooling Efficiency in Cold Regions
Well water and geothermal heat maintain stable temperatures throughout the year. Well water is used directly as medium-temperature chilled water for air conditioning, minimizing the operating time of heating and cooling units as much as possible (free cooling).
During extreme heat and in winter, high-efficiency heat pumps that utilize well water—which is unaffected by outside air—are operated for heating and cooling.
In addition, fresh outdoor air is drawn in through an underground pit and pre-cooled or preheated using geothermal heat (Cool-Heat Trench).

③ Adoption of an HVAC system that flexibly adapts to seasonal and operational changes
For the outside air introduced into the rooms, we use a total heat exchanger that exchanges heat with the air exhausted from the rooms, and we adjust the volume of outside air based on the number of occupants (CO₂ concentration control).
Since there are significant temperature differences between morning and evening during Hokkaido’s transitional seasons (spring and fall), the building features an air conditioning system that allows users to choose between medium-temperature chilled water and hot water for flexible heating and cooling.
Additionally, on the first floor, we combine this system with underfloor radiant heating and cooling that utilizes well water heat, thereby enhancing energy efficiency and comfort.

④ Maximizing Natural Light and Minimizing Lighting Energy Consumption
Soft natural light enters the offices from the inner terrace on the west side. Furthermore, skylights are installed above the stairwells within the offices, allowing natural light to reach the far corners of the rooms and creating a healthy lighting environment.
The lighting control system minimizes lighting energy consumption through daylight-based control and occupancy detection, in addition to controls designed to regulate occupants’ circadian rhythms.

・Construction Site: 3-6, Kita 2-jo Nishi 14-chome, Chuo-ku, Sapporo
・Structure: Reinforced concrete (RC), with some wooden and steel-frame sections
・Number of Stories: 3 stories above ground
・Building Footprint: 503.26 m²
・Total Floor Area: 1,382.57 m²
・Contractor: Obayashi Corporation, Sapporo Branch
・Scheduled Completion: November 2025