Commercial store Netherlands

Builders’ merchant “Centen” achieving energy-label A

Builders’ merchant “Centen” achieved Energy-Label A (from E). The EnerTwin provided two Label-steps with its easy plug&play installation on the existing heating-system. The EnerTwin cuts on the edges, covering both the charging of the forklift while providing heat to the building.


According to the Energy Performance of Building Directive (EPBD, Europe), Commercial office buildings require energy label improvement to label C by 31-12-2022 ultimately. This applies to all existing office buildings. Monuments and historic heritage are exempt from the implementation of EPBD.

Companies are increasingly faced with CSR and environmental challenges by customers as well as shareholders and local authorities. Reduction of the company carbon footprint (both CO2 and NOx emissions) is on management agenda’s.

The Use Case

  • Location: construction materials company with office and showroom, Wanroij, The Netherlands
  • Goals: The company formed a project team charged with finding the best fitting solution for the identified challenge and thereby involving the local operational team in the project. The challenge was initiated by replacement of a traditional condensing boiler due to age. With the implementation of EPBD for this building coming up, combined with the sustainability plan of the company a more radical change was due. The company required strong improvement of the Energy-label and together with the building owner, various options were investigated. Silent operation, as the unit would be operating in the proximity of the office staff, was mandatory. The company expected strong changes in the energetic sector driving towards sustainability and required a product that was adaptive to future developments like green gas and hydrogen mixes.
  • Solution: Engine-based CHP systems were unsuitable for th silent operation requirement. The building would also not allow for costly changes for low-temperature systems that are required by other systems such as heatpumps. EnerTwin was therefore chosen.

The installation and role of the EnerTwin

EnerTwin is connected to the heating circuit through a buffer tank. It provides base load heat for the office and showroom. It replaced an old boiler and combined with other adjustments, the energy-label improved from “E” to “A”, making the building therefore compliant to the upcoming 2023 regulations for existing office-buildings. EnerTwin’s contribution in this energy label upgrade is 2 label steps. The produced electricity is used for charging the electric forklift and to provide power to the offices and showroom. 

Factual results of the project

  • Energy label: confirmed and certified at label A
  • Installation costs: € 3200
  • Annual running hours: 4500-5000 hrs
  • Additional condensing boiler installed for peak-demand
  • Reliable heating solution covering 95% of heatload
  • Subventions have been granted
  • Reduction of energybill at 115% of planned
  • Climate goals have been achieved with CO₂ and NOₓ emissions reduced by 9,5 Tons a year
  • Silent operation, inaudable for office staff
  • Plug&Play installation with little impact on operations of the company

The project team feedback

  • Sustainability goals for the company were considered an import step into the future of the company. Charging the forklift and their EV’s whilst the building was heated by the EnerTwin at high efficiency was a very satisfying concept for the team.
  • The results that surfaced after the first year of operation regarding CO2 reduction based on the runhours were impressive. By installing a buffervessel, the runhours created more continuous operation and more runhours.
  • Management reported better than expected financial results due to the overshoot in runhours.
  • The building-owner was positively surprised by the impact on the end-users and ease of implementation, considering application in other commercial real-estate in their portfolio.


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