Method for cost-optimal retrofitting

DESCRIPTION:

A two-step methodology that aims to select the cost-optimal solutions for retrofitting of buildings in large-scale renovation process (200-300 dwellings). From a set of different potential combinations of passive elements (e.g., adding different insulation materials with different thickness and/or windows) and active elements (e.g., heat pumps / multi-split air conditioning for heating, cooling and DHW and/or photovoltaics), the methodology helps to select the most appropriate combination considering the energy performance and economic parameters. The process aims to select solutions that achieve a 50% reduction in the energy demand and/or a significant improvement in the thermal comfort conditions. A detailed economic model is part of the methodology giving as a result the following outputs: investment costs deducting grants for each owner and life cycle global costs.

VALUE

The method aims to support the process of selecting the most appropriate technical solutions considering both energy performance and economic parameters. Getting good estimations of the investment to be done by end-users is a key element for deciding to retrofit the buildings. The detailed economic information is also a key element for the public and private entities which are promoting the large-scale retrofitting process, meaning local public administration, and retrofitting agents, in the framework of Public Private Partnerships.
The conceptual scheme adopted for integrated energy design.
Investment per dwelling vs. non-renewable primary energy use in different renovation scenarios.

APPLICATION

The method and its results aim to increase the skills and the knowledge of the key actors in large-scale retrofitting processes. Once adjusted to the building archetypes in a district, the methodology and the tools can be applied to other districts in the same city or in other municipalities. The method includes and economic model estimating: (i) Final investment for owners considering different levels of grants which are energy performance dependent, in Euros/dwelling; (ii) Monthly owner’s payment quote which depends on the funding scheme, in Euros/dwelling; and (iii) Global costs, considering the initial investment, energy savings, replacements, and maintenance costs.

POTENTIAL IMPACT

Thanks to:

FUNDING: