**A Functional Data Analysis for Assessing the Impact of a Retrofitting in the Energy Performance of a Building**

**Miguel Martínez Comesaña 1,\*, Sandra Martínez Mariño 1, Pablo Eguía Oller 1, Enrique Granada Álvarez 1 and Aitor Erkoreka González 2**


Received: 13 February 2020; Accepted: 19 March 2020; Published: 7 April 2020

**Abstract:** There is an increasing interest in reducing the energy consumption in buildings and in improving their energy efficiency. Building retrofitting is the employed solution for enhancing the energy efficiency in existing buildings. However, the actual performance after retrofitting should be analysed to check the effectiveness of the energy conservation measures. The aim of this work was to detect and to quantify the impact that a retrofitting had in the electrical consumption, heating demands, lighting and temperatures of a building located in the north of Spain. The methodology employed is the application of Functional Data Analyses (FDA) in comparison with classic mathematical techniques such as the Analysis of Variance (ANOVA). The methods that are commonly used for assessing building refurbishment are based on vectorial approaches. The novelty of this work is the application of FDA for assessing the energy performance of renovated buildings. The study proves that more accurate and realistic results are obtained working with correlated datasets than with independently distributed observations of classical methods. Moreover, the electrical savings reached values of more than 70% and the heating demands were reduced more than 15% for all floors in the building.

**Keywords:** retrofitting; refurbishment; functional data analysis; vectorial analysis; energy efficiency
