Rising electricity prices alongside an increasing environmental awareness have sparked numerous initiatives from consumers to adopt clean energy resources. Additionally, consumers have begun to take a more proactive role in their own electricity generation. They are also more cognisant of how efficiently they generate and use energy. Several households and organisations around the world have embraced the use of solar panels as a means for generating clean and sustainable energy. Analysing data gathered from these panels can reveal valuable insights into their operating performance. In this paper, we develop a data-driven framework to shed light on the performance of photovoltaic (PV) panels and demonstrate its general applicability using three different data sets spanning several months obtained from panels situated in diverse geographies. We show how the framework can be used to infer the operational efficiency of solar panels for home owners and facility managers of commercial organisations alike.