Cost-Effective Energy & CO2 Emissions Optimization in Building Renovation

Completed (2010 - 2017)


In recent years, various standards and regulations for energy consumption in buildings have emerged that specify greatly improved levels of energy efficiency in comparison with earlier requirements. However, these mainly focus on new buildings and do not respond effectively to the numerous technical, functional and economic constraints of the existing stock. It is common that requirements for existing buildings, which are generally targeted at energy efficiency measures, result in expensive processes and complex procedures, seldom accepted by occupants, owners or developers.

But, with an objective of mitigating climate change, renewable energy supply measures can sometimes be at least as cost effective as energy conservation and efficiency measures, if not more so. Therefore, in existing buildings, the most cost-effective renovation solution is often a combination of energy efficiency measures and renewable energy supply measures.

Hence, it is important to investigate where balance point lies between these two types of measures from a cost-benefit perspective. This involves determining how the best performance (in terms of less energy consumption, less carbon dioxide emissions and overall added value achieved by the renovation) would be achieved with the least effort (in terms of investment, interventions in the building and disturbance of occupants). Therefore, a new methodology for energy and carbon dioxide (CO2) emissions optimized building renovation, as a basis for future standards, will be developed to be used by interested private entities and agencies for their renovation decisions, as well as by governmental agencies for the definition of regulations and their implementation.


The project objectives are to:

  • Define a methodology for establishing cost optimized targets for energy consumption and CO2 emissions in building renovation;
  • Clarify the relationship between CO2 emissions and energy targets and their eventual hierarchy;
  • Determine cost effective combinations of energy efficiency and renewable energy supply measures;
  • Highlight additional benefits achieved in the renovation process;
  • Develop tools to support decision makers in accordance with the developed methodology;
  • Select exemplary case studies to encourage decision makers to promote efficient and cost effective renovations.


The project is mainly focused on both single and multifamily residential buildings. Simple office buildings without complex HVAC systems are also in the scope of this project, if relevant, and useful information can be extracted from them. This would demonstrate the applicability of the developed methodology and tools to non-residential buildings.


The project objectives, scope, work methodology and deliverables have been established.The basis of the methodology is being agreed, particularly concerning the cost optimization of energy consumption and CO2 emissions targets.A number of case studies are being developed.As it has been identified at an early stage that indicators and metrics vary from country to country, a glossary is being created to establish a common approach and a common language to enable meaningful comparisons of information and results.To communicate progress, a project website is under development and the first in a series of newsletters is being prepared.

Operating Agent

Manuela Almeida
Department of Civil Engineering
University of Minho
Campus de Azurém
4800-058 Guimarães


Austria, P.R.China, Czech Republic, Denmark, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland