Few houses have been built in the Spanish Mediterranean in accordance with the Passivhaus (PH) standard. This standard is adapted to the continental climates of Central Europe and thorough studies are necessary to apply this standard in Spain, especially in the summer. High relative air humidity levels in coastal areas and solar radiation levels of west-facing façades require adapted architectural designs, as well as greater control of air renewal and dehumidification. A priori, energy consumptions undergo big variations. In this study, the construction of a single-family house in the Spanish Levante was analysed. All enclosure layers were monitored using sensors of surface temperature, solar radiation, indoor and outdoor air temperature, relative humidity, and air speed. The thermal behaviour of the façade enclosure and air infiltration through the enclosure were examined using the blower door test and impacts on annual energy demand were quantified. Using simulation tools, improvements are proposed, and the results are compared with examples of PH housing in other geographical areas. The annual energy demand of PH housing was 69.19% below the usual value for buildings in the Mediterranean region. Very thick thermal insulation and low values of airtightness could be applied to the envelope, which would work very well in the winter. These technique solutions could provide optimal comfort conditions with a well-designed air conditioning system in summer and low energy consumption.

The infrastructure of the Británica warehouses in Alicante is a very important industrial architectural element in the history of Spain, although it is unknown to almost all of the inhabitants of the city. The former fuel refinery is located in the Serra Grossa Mountains and served much of the country until 1966. This research is based on the plans of the city of Alicante to convert a historical element, the Británica warehouses, into a unique tourist site. Currently, the network of storage domes in this facility, which has an approximate footprint of 20,000 m 2 and domes approximately 20 m high, is in a state of neglect, and there are neighborhood initiatives for its rehabilitation to become a cultural or tourist site. Therefore, it is necessary to take into account the quality of the indoor air. Radon gas is analyzed as a control element for future refurbishment of the facility. Alicante is a nongranite area and therefore is not very susceptible to generation of radon gas indoors, but the conditions of a buried and poorly ventilated space make the site appropriate for analysis. Most scientific agencies in the field of medicine and health, including the World Health Organization, consider radon gas to be very harmful to humans. This element in its gaseous state is radioactive and is present in almost all the land in which the buildings are implanted, with granitic type soils presenting higher levels of radon gas. Nongranitic soils have traditionally been considered to have low radon levels. The city of Alicante, where the installation is located, is a nongranitic area and therefore is not very susceptible to generating radon gas in buildings, but the conditions of buried and poorly ventilated places make the site appropriate for analysis to support air quality control and decision-making.