Reliability of Energy Efficient Building Retrofitting - Probability Assessment of Performance & Cost (RAP-RETRO)

Completed (2010 - 2015)


Retrofit measures are therefore of the utmost importance for upgrading the building stock. But, many building owners are only interested in the initial capital cost. Looking at the risks associated with the actual performance of such measures and the costs incurred highlights the need for life cycle thinking. So, applicable calculation methods are required in this area. For this purpose, probability assessment in life cycle costing of solutions supports sound decision making relating to investments. For industry, customer relationships are based on future expectations and confidence. These need to be supported by proper probability assessments.

The project has significantly improved methods and tools for integrated evaluation and optimization of retrofitting measures, including energy efficiency, life cycle cost and durability. For decision makers, designers and practitioners, it has demonstrated the benefits of the renewal of the existing building stock and how to create reliable solutions.

The project has delivered decision support data and has developed tools for evaluating energy retrofitting measures, focusing on residential building envelopes. These tools have been based on probabilistic methodologies. The main results of such probabilistic risk assessments are probabilities or likelihoods, i.e. quantities that show how many out of all the possible cases do or do not meet the desired performance.

Specifically, the project has:

  • developed and validated probabilistic methods and tools for prediction of energy use, lifecycle cost and functional performance based on assessment of energy retrofitting measures,
  • applied and demonstrated probabilistic methodologies on real life case studies to enhance energy savings, secure performance and apply cost analyses, and
  • created guidelines for practitioners, including assessment of common retrofitting techniques.

Operating Agent

Dr. Carl-Eric Hagentoft
Chalmers University of Technology
Department of Civil & Environmental Engineering
SE-412 96 Göteborg


Austria, Belgium, Denmark, Germany, the Netherlands, Portugal, Sweden, United Kingdom, USA