This paper seeks to extend the definition of a sub-centre beyond the usual definition as a place with significantly larger employment density that has an effect on the overall employment density of the nearby locations. Together with the previous conditions, it is suggested that it is necessary to include another which represents a structural element of an urban sub-system within the metropolitan configuration—that is, a place with intense spatial interaction with its hinterland. Therefore, a metropolitan area can be seen as one comprising urban sub-systems characterised by greater or lesser polycentrism. In this paper, a ‘bottom—up’ methodology based on commuter flows is proposed in order to detect metropolitan sub-centres. Using empirical data from the Metropolitan Region of Barcelona, the proposed methodology is tested, comparing its results with those of other commonly used methodologies (cut-offs, parametric and non-parametric models). The results suggest that the proposed methodology permits optimising the sub-centre delimitation process.

In the literature, there is extensive, although in some cases inconclusive, evidence on the impact of Energy Performance Certificates (EPC) on housing prices. Nonetheless, the question of whether such an impact is homogenous across residential segments remains highly unexplored. This paper addresses this latter issue utilizing multifamily listing data in metropolitan Barcelona. In doing so, first the entire sample is analyzed using a hedonic model. Second, the sample is split on the basis of a multivariate segmentation. Finally, separated hedonic models are specified again. The results suggest that in general, there is a modest impact of EPC ratings on listing prices, nonetheless it is not homogeneous across housing segments: (1) for the most modern apartments, with state-of-the-art features and active environmental comfort, energy ratings seem to play a null role in the formation of prices; (2) conversely, for the cheapest apartments, apartments boasting the most basic features, and apartments located in low-income areas, the “brown discount” is enormously significant, potentially depreciating the equity of those who have the least resources to carry out an energy retrofit. These results have implications for the assessment of the EPBD and its Spanish transposition, since a very well-intentioned environmental policy could have potentially harmful social repercussions in the absence of corrective measures.

Energy performance certificates (EPCs) are important tools aimed at improving buildings’ energy performance. They play a central role in the context of the Energy Performance of Buildings Directive (EPBD) which asks member states (MS) to take the necessary measures to establish a complete certification system. In this study, an application of the hedonic price method (HPM) assessing the effect of energy labels derived from the EPC on real estate market value is presented. The estimation methodology was applied to two European cities characterized by different climate conditions. The analysis was based on two datasets of listing prices referring to multi-family residential markets in Turin (Italy) and Barcelona (Spain). Four models for each dataset were applied to capture the marginal price of green attributes, but also to control for the spatial autocorrelation among values. The findings showed how the EPC has been applied in the two countries and how it has influenced the real estate market. Turin’s buyers pay more attention to the EPC label, while in Barcelona, they value much more single characteristics, such as air conditioning and a swimming pool, considered popular attributes among contemporary buildings in this climate zone. From the results, it is possible to deduce that the implementation of the EPC schemes is still irregular in EU countries and must be strengthened through a standardized rating model.

In attempts to improve the energy efficiency of protected historical buildings, two barriers arise. The first is the restrictions imposed by authorities that are responsible for cultural heritage preservation. The second is the exclusion of protected buildings from strict compliance with energy efficiency requirements in current regulations, such as the issue of an Energy Performance Certificate, which removes them from conventional channels of public policies. Both of these issues put heritage in a delicate situation, especially when they are intended for privately developed residential uses. This paper presents a methodology for assessing and establishing a trade-off between energy performance and the cultural value of heritage buildings through the comprehensive analysis of a case study: the retrofitting of Can Armengol Palace in Palma de Mallorca (Spain). The study revealed (1) the need to objectify the cultural values of the building as far as possible to identify conflicts with the strategies of energy efficiency improvement; and (2) the appropriateness of considering every aspect of a rehabilitation intervention in a global simultaneous approach, not just energy aspects. The method that was used had five steps: acquiring a deep knowledge of the building configuration, assessing the building performance for every legal requirement, identifying cultural values, defining intervention criteria, and analyzing intervention effects on the protected elements of the building. The most important contribution in this study is the detailed and extended definition of architectural heritage values and the consideration of interventions resulting from sustainability retrofits as a new kind of value, that reflects current worries, for which future generations will remember us.

Este artículo estudia de forma pionera en España la incidencia de la calificación energética sobre los valores residenciales. Para ello se analizan, mediante un modelo hedónico, datos de precios de venta de la Barcelona metropolitana. Los resultados sugieren que pasar de una calificación G a una A incrementa el valor en un 5,11 %, equivalente de media a 16,07 euros/m2/escalón (aunque existe un extra para las viviendas A). Este sobrevalor es, en términos relativos, muy inferior al de otras ciudades europeas y, en términos absolutos, menor que los sobrecostes relativos una mejora en la calificación energética reportados previamente. Además, la enorme ausencia de información energética en la comercialización parece responder a una estrategia para ocultar la pobre calificación del parque edificado y agravar la asimetría informativa. Todo junto ensombrece la eficacia de la Directiva Europea de Eficiencia Energética tal como ha sido transpuesta en nuestro país, y clama por su rediseño.