Demonstration site #2 is an apartment block located in the city of Cádiz, in the southern cost of Spain. The de-monstrator building has a built area of 1889 m2 from which 1077 m2 correspond to a residential use of 22 apart-ments in 4 floors. The whole building belongs to the social housing programme of the City Hall of Cádiz and there is an approved rehabilitation plan consisting on: replacement of windows, increase of the insulation level in façade walls and roof, installation of a centralised system for DHW based on renewable source (solar thermal system or similar), etc. It is expected that this rehabilitation plan will be started in 2018. As with most of the social housing in southern Spain, the demonstrator building does not have any centralised system for space heating and cooling.

This situation can be explained due to 2 main reasons: First and foremost, this is due to the lack of financial possibilities of the owners, considered to be in the conditions known as ‘energy poverty’. This situation, along with the fact that the building envelope is poorly insulated, implies that thermal comfort conditions are hardly achieved. The sec-ond reason is enabled by the relatively mild weather conditions of the city. Both winter and summer weather condi-tions are influenced by a Mediterranean climate and softened by the proximity of the sea. As a consequence, the typical heating system is a portable electrical radiator, while in the summer months, there are not any dedicated cool-ing systems in place except for conventional cooling fans. For the production of DHW, each apartment has its own individual natural gas boiler installed, typically characterized by poor energy efficiency.

At the present moment there is an approved preliminary rehabilitation plan for this building consisting of the replacement of the current windows from single glazing to double glazing, the increase of the insulation level in façade walls and roof to the national standard limits, installation of a centralised system for DHW based on renewable source (solar thermal system or similar), etc. It is expected that this rehabilitation plan will commence in 2018. The RECO₂ST objective is to re-assess the approved rehabilitation plan in order to guarantee to achieve Near Zero Energy Demand conditions from the perspectives of Cost Effectiveness, Environmental benefits, and Modular construction. To avoid any need for SHC, the CADIZ Retrofit-Kit will be centred around the use of roof and façade wall insulation, as well as VTLV windows and tapping the strong solar potential of the area.