The research has received funding from the Seventh Framework Programme (FP7/2007-2013) under grant agreement n° [314363].

Evaluation of demonstration projects shows promising results

As the demonstration buildings are moving towards their completion, a technical evaluation of the retrofitting projects show promising results. The report “Technical evaluation and general recommendations on retrofitting measures” presented by WP3 also points at experiences and recommendations to be used in the forthcoming work within ZenN.

Within task 3.1, the retrofitting projects of WP2 are evaluated on their energy saving potential, economic feasibility and environmental performance. The calculated values of this technical evaluation will later be compared to monitored values after renovation in Task 3.3. The results confirm some of the identified barriers and challenges from D1.1, while also showing that renovation with ambitious targets for energy efficiency and environmental performance can be technically and economically feasible.

The report evaluates the technical aspects of nearly Zero Energy Building Renovation in the participating demonstration districts in Malmö, Eibar, Grenoble and Oslo. The proposed measures and their integration in the whole district are analyzed by calculating a set of indicators, which are:
•    Energy efficiency measures, considering the resulting balance between delivered energy and produced energy
•    Energy efficiency economics, including investment costs, payback time, and lifecycle costs, and
•    Environmental performance, analyzing the reduction of primary energy use and GHG emissions.

Results from the evaluated indicators for the final technical approach to be implemented.

"The overall results so far are promising and in line with expectations stated in the beginning of the project.” says Peter Sandö, task leader at IVL Swedish Environmental Research Institute. “The reduction in greenhouse gas emissions for example is encouraging. At the same time, one notable barrier is the long payoff time, confirming results from deliverable 1.2 that economics and financing opportunities are a major obstacle and challenge to nZEB renovation projects.”

The experiences and conclusions made during the process of this deliverable will be used in the development of guidelines in WP5 and replications plans in WP6. The recommendations cover such varying aspects as:

  • The importance of involving building owner, tenants and expertise in energy efficiency at an early stage to find optimal solutions.
  • Setting initial requirements and targets in terms of reduction in delivered energy, primary energy and GHG emissions.
  • A focus on the reduction of heat losses, thereby prioritizing energy demand.
  • Sufficient ventilation is crucial, when insulation thickness and airtightness increase, in order to avoid poor indoor air quality and moisture related problems.
  • Heat recovery from the exhaust air should always be considered, especially in Northern Europe.
  • Exhaust air heat pumps can be a cost-efficient solution for heat recovery. However, the significant increase in use of electricity usually affects the environmental performance negatively.
  • Renewable energy can be produced on-site, e.g. solar energy for electricity or heating. Renewable energy can also be a part of the connected energy system, such as district heating.
  • Possible collaborations between building owner and energy suppliers in finding the best possible solutions should be explored.

“This final point might turn out to be a highly relevant conclusion of the project”, says Peter Sandö. “This is a potential win-win situation, where collaboration can have great impact on district level by avoiding sub-optimisation and supporting replication”.

For more information: Peter Sandö, IVL,

Updated: 2015-05-07


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