According to the European Union, household energy consumption accounts for up to 30% of total energy consumption. Therefore, the household sector has great potential for reducing greenhouse gas emissions. The introduction of energy efficiency measures and the renovation of multi-apartment buildings are important solutions for reducing greenhouse gas emissions and achieving climate neutrality in Latvia. However, this potential is not being fully exploited because the renovation process in the multi-apartment building sector is extremely slow. One of the reasons for this is the lack of interest and willingness of residents to engage and agree on the implementation of energy efficiency measures in buildings. The study examines the main groups of energy consumers, their definitions, needs, as well as the most common obstacles and barriers that prevent energy consumers from fully engaging in the implementation of energy efficiency measures. To get an idea of the groups, publicly available information on the characteristics of hard-to-reach consumers was analysed, media content was analysed and interviews with energy experts were conducted. The results showed that the literature mentions different definitions, audience characteristics, barriers, and needs of hard-to-reach energy consumers. These definitions, barriers, and needs vary across countries and research contexts. There is a strong focus on overcoming barriers, but little research on the needs of the groups. Defining the audience accurately and studying the needs of the groups in depth are essential steps in developing and implementing appropriate policies for engaging hard-to-reach energy consumers. These findings highlight an important knowledge gap in this research field.