Energy Efficiency: A Building with History and Evolving Needs
The property Ultuna 2:26, located in Uppsala, Sweden, consists of several interconnected building sections that have been gradually extended since the original construction in 1947. The premises were previously used for scientific research and have since been renovated for their current use as a school, with Internationella Engelska Skolan as the tenant. The total building area is approximately 7,200 m² (Atemp).
Reference 9.9.2025
About the project
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Client
Stenvalvet – Ultuna 2:26
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Objective
Reduce the building’s high energy consumption.
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Rejlers role
Energy audit, design engineering and project management.
A property with high energy consumption
In autumn 2020, Stenvalvet and Rejlers initiated a collaboration to reduce the building’s high energy use. The project was delivered as an energy partnering assignment with Rejlers Energy Projects as the EPC contractor, carried out in two phases:
Phase 1: Energy audit and development of proposed measures
Phase 2: Design engineering and implementation of selected measures
Smart measures for improved energy performance
The energy audit, carried out according to the Belok total methodology, resulted in 13 detailed proposals and several additional observations. Most of these proposals were selected for further design and implementation:
- Sealing and insulation of open shafts and improvements to roof penetrations
- A major refurbishment replacing the existing ventilation system (supply in the basement and exhaust fans on the roof) with two new heat recovery ventilation units
- Multiple unit replacements and demand-controlled ventilation
- Renovation of the district heating substation and replacement of outdated control and monitoring equipment
- Replacement of thermostatic valves and balancing of the heating system
- Installation of radiators and heat strips in areas previously heated by air systems
- Connection of existing control and monitoring systems
Sustainable operation and improved indoor environment
The project has resulted in a significant reduction in energy use, lower maintenance requirements and an improved indoor climate for tenants. Energy savings amount to approximately 1,100 MWh per year, corresponding to a reduction of around 50 percent in the building’s heat consumption.
For Rejlers, the project has led to continued cooperation with both the property owner Stenvalvet and the tenant. The project has also strengthened collaboration internally within Rejlers, where our role as EPC contractor has demonstrated our capability to take full responsibility and deliver energy efficiency projects from start to finish.
Contact us
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Jonas Holmstedt Head of Buildings, Sweden Send email: Jonas Holmstedt Call: + 4 6 7 2 0 5 0 2 2 4 5 Sweden
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