Rejlers examined the impact of design solutions on the carbon footprint of HOAS’ new building

The foundation for student housing in the Helsinki region (Hoas) wanted to examine the effects of different design solutions on the life-cycle carbon footprints of its new buildings. Rejlers’ study provided Hoas with an understanding of how to reduce its carbon footprint and how this impacts costs. 

HOAS wanted to find out how to reduce the life-cycle emissions of its new buildings by ten per cent from the current level. The foundation was also interested to know how a new building with the current solutions stacks up against the City of Helsinki’s upcoming carbon footprint limit value for new buildings.  

Rejlers conducted a study to compare six design solutions. The building’s life-cycle emissions were calculated using the Ministry of the Environment’s 2021 low-carbon assessment method. The building’s carbon footprint with HOAS’ current design solution is 16.47 kg CO2e/m2/a; with the lowest-emission alternative, it would be 13.65 kg CO2e/m2/a. 

“Rejlers’ study provided information on the initial state of our new building and the action we could take to reduce emissions. For example, our choice of heating system or low-emission materials in the building could reduce the carbon footprint,” says Marika Nyyssönen, Sustainability Manager at HOAS.  

“A wholesale reform of construction legislation is underway, so many construction projects already need to include low-carbon assessments. Controlling low-carbon construction and calculating emissions in light of the costs play a key role in construction, and this addition will generate clear added value for building owners, as well as higher rent revenues,” says Ville Alho, Group Manager of Energy and Life Cycle Services at Rejlers. 

The study also compared the investment and life-cycle costs of various design solutions. HOAS found this extremely important. 

“The study found that the form of energy production has the greatest impact on life-cycle emissions. For example, emissions can be reduced by using heat pump technology and hybrid solutions for energy production. However, these solutions also raise the investment cost the most,” ponders Alho. 

The study provided Hoas with valuable information to support the design of new buildings, which must cope with several simultaneous constraints. For example, the energy efficiency benchmark for Hoas’ new buildings must be class A. The report gave a good picture of how different goals can be reconciled and what design solutions can be used to achieve them. 

“We gained information about how different solutions and materials affect emissions and costs, and an understanding of which direction to head in. We will use this knowledge in our design work and to support decision-making,” says Marika Nyyssönen, Sustainability Manager at HOAS. 

Rejlers prepared a clear final report, which will help Hoas in the further planning of the site.  

“The results are presented clearly and are easy to understand. We reviewed the questions that arose from the report together. It was very beneficial for us,” Nyyssönen says.

Images: by HOAS