# Monitoring a Pre-Normative Multi-Family Housing Case-Study in a Mediterranean Climate
## 2 Case Study  
The case-study building lies within a group of dwellings named \"La Estrella\", which encloses 432 housing units, commercial premises and storage rooms (Figure 1). This building was constructed between 1955 and 1963 in Seville by the [PERSON] brothers, members of the \"OTAISA\"emblematic group of architects. It is included in the Docomomo Iberico database [25] and the Andalusian Heritage Building database [26] with Registration Number 01410910216. The star-shaped towers reinterpret the \"H\" block typology (Figure 2): the three wings connected by a vertical communication core offer a wide variety of orientations, while the double corridor eases indoor ventilation. The buildings have an accessible inverted roof and a double-layer brick facade with an intermediate air chamber as its envelope solution, which was an improvement on the widespread 1950s' constructive solution of single-layer brick walls. However, due to the fact that these buildings were constructed before the NBE-CT-79 mandatory regulation on thermal conditions in buildings, no kind of thermal insulation is present. In order to run the monitoring campaign under real use and operational conditions and to record environmental parameters, two dwellings located on the first floor in Block 2 were selected. Figure 1: Bird’s eye view of residential complex La Estrella. Figure 2: Plan of the residential complex with monitored dwellings and prevailing winds. Each dwelling accounts for an approximate surface of 100 m\({}^{2}\), with a southeast orientation in Flat A and a south orientation in Flat B (Figures 3 and 4). The rooms that have been monitored in each dwelling are the bedroom (DVA in flat A; DVB in flat B) and the living-room (SVA in flat A; SVB in flat B). The selected dwellings have largely remained as originally built in terms of indoor distribution and thermal envelope; however, in 1984, steel window frames were replaced by others of anodized aluminum without any thermal bridge break, with approximately 4-6 mm single glazing. Today, these single-glazed windows remain in Dwelling B, while Dwelling A's windows were updated in 1996 to incorporate 6-6-6 mm double glazing. There is a further issue to consider regarding the energy performance of the envelope, which is the existence of blind boxes in the bedroom windows. In terms of energy performance, they act as highly ventilated air chambers and facilitate air filtrations. In the selected dwellings, only the bedroom windows feature these boxes. In order to assess the energy behavior of the walls, transmittance values have been calculated [27] (Table 1). Appendix D from \"CTE DB-HE1 2013\" [28] has been taken as a reference to determine their discrepancies from Spanish regulation energy-demand limitations. To this end, Seville's climate zone should be considered according to the Spanish regulation. Spanish climate zones are labelled with a letter, from A-E, which corresponds to an increasing scale of winter climate severity, and a number, from 1-4, for an increasing scale of summer climate severity. In this case, Seville is in the B4 climate  
Figure 4: Thermal envelope definition. Figure 3: Floor plan with monitored dwellings. zone, with Mediterranean weather conditions, where summers can reach very high temperatures (over 40 \({}^{\circ}\)C) and where the region enjoys mild winters. The subsequent comparative analysis shows the degree of influence exerted by the lack of thermal insulation in the buildings. As a result, the wall transmittance is double that of the maximum value established by the aforementioned regulation, which has an immediate effect on increasing energy gains and losses in the dwellings. To evaluate the openings, the following parameters have been calculated: transmittance value for the glass (U\({}_{\text{g}}\)), transmittance value for the frame (U\({}_{\text{f}}\)), transmittance value for the opening (U\({}_{\text{W}}\)) percentage of surface of each element of the window (%), solar factor of the glass (g), frame factor (FM) and solar absorptivity.