The research about energy efficiency in buildings has exponentially increased during the last few years. Nevertheless, both research and practice still cannot rely on complete methodologies tailored for building portfolios as a whole, because the attention has always been drawn to individual premises. Yet, energy efficiency analyses need to go beyond the single building perspective and incorporate strategic district approaches to optimize the retrofit investment. For this purpose, several aspects should be considered simultaneously, and new methodologies should also be promoted. Therefore, this paper aims to discuss energy retrofit campaigns in building portfolios, drawing an exhaustive and updated review about the challenge of jumping from the single-building perspective to a stock-based analysis. This research discusses the publications available on the topic from five key aspects that are all essential steps in achieving a complete and reliable study of energy efficiency at a portfolio level. They are energy modelling and assessment, energy retrofit design, decision-making criteria assessment, optimal allocation of (financial) resources and risk valuation. This review, therefore, advocates for joint consideration of the problem as a basis on which to structure further disciplinary developments. Research gaps are highlighted, and new directions for future research are suggested.

Purpose: Valuation is the process of determining Market Value. Property valuation, as with the valuation of all assets, is an estimation of price in the market. It is value in exchange. The valuer role is to determine the appropriate approach, the method and use the right model to achieve this aim as best as possible. It is a combination of analysing the market and determining the critical variables for the valuation method/model. The method is separate from the valuation process which should be followed (according to the International Valuation Standards Council Valuation Standards) regardless the valuation method chosen. There are valuation approaches, valuation methods and, as a subset of the methods, techniques or models.Design/methodology/approach: This practice briefing is an overview of the Valuation Methods and Models available to the valuer and comments on the appropriateness of valuation each in assessing Market Value for specific property types.Findings: This briefing is a review of the valuation methods and models and models that can be applied to determine market value.Practical implications: The role of the valuer in practice is to identify the method of valuation and then apply the correct mathematical model for the valuation task in hand.Originality/value: This provides guidance on how valuations can be presented to the client in accordance with the International Valuation Standards.

Purpose: Since the global financial economic crisis hit the world markets in 2007/2008, the role of property valuation has been under greater and greater scrutiny. The process of valuation and its quality assurance has been addressed by the higher prominence of the International Valuation Standards Council (IVSC). This is a significant initiative worldwide. However, there has been little written on the appropriate use of valuation approaches and methods in market valuations. There is now a hierarchy of valuation definitions. In order, there are valuation approaches, valuation methods and, as a subset of the methods, techniques or models. The purpose of this paper is to look at the importance of identifying the appropriate approach to be adopted in market valuations and the methods, techniques and models that should be applied to determine market value. Design/methodology/approach: This practice briefing is an overview of the valuation approaches, methods and models available to the valuer and comments on the appropriateness of valuation each in assessing market value. Findings: This paper reviews the IVSC-recognised approaches and prompts the valuer to be careful with the semantics involved so that they are better placed to provide an unambiguous service to their clients. Practical implications: The role of the valuer in practice is to identify the appropriate approach for the valuation of the subject property, choose the right method and then apply the correct mathematical model for the valuation task in hand. Originality/value: This provides guidance on how valuations can be presented to the client in accordance with the International Valuation Standards.

Building energy modeling (BEM) is used to support (nearly) zero-energy building (ZEB) projects, since this kind of software represents the only available option to forecast building energy consumption with high accuracy. BEM may also be used during preliminary analyses or feasibility studies, but simulation results are usually too detailed for this stage of the project. Aside from that, when optimization algorithms are used, the implied high number of energy simulations causes very long calculation times. Therefore, designers could be discouraged from the extensive use of BEM to conduct optimization analyses. Thus, they prefer to study and compare a very limited amount of acknowledged alternative designs. In relation to this problem, the scope of the present study is to obtain an easy-to-use tool to quickly forecast the energy consumption of a building with no direct use of BEM to support fast comparative analyses at the early stages of energy projects. In response, a set of automatic energy assessment tools was developed based on machine learning techniques. The forecasting tools are artificial neural networks (ANNs) that are able to estimate the energy consumption automatically for any building, based on a limited amount of descriptive data of the property. The ANNs are developed for the Po Valley area in Italy as a pilot case study. The ANNs may be very useful to assess the energy demand for even a considerable number of buildings by comparing different design options, and they may help optimization analyses.