Access to energy services is determinant for household’s development; hence, it is also a source of inequality. A household’s economy is aggravated when encountering energy affordability constrains such as the replacement of modern but more expensive fuels for less expensive or freely available ones, budget sacrifices on their basic basket choices, and in some cases, even falling into debt trying to fulfil all their energy and non-energy needs, which consequently leads to energy poverty. This paper starts by reviewing the energy poverty literature on metrics, conceptualisations, and the use of indicators. It then focuses on transferring prevailing expenditure-based approaches from Europe to calculate the energy poverty ratio of Mexican households, applying the metrics 2M, M/2 exp. and LIHC. Most importantly, it proposes a new Low-income Low-Cost (LILC) metric, with the purpose of recognizing household’s mistaken energy poverty due to energy-efficient buildings. It further captures the most relevant drivers through a logit analysis and defines the required investment to tackle energy poverty. This paper seeks to retrieve existent underutilized literature and measurement approaches from Latin American countries, and transfer new insights applying European metrics to non-European context.