The aim of this review is to provide an overview of the literature on hard-to-reach (HTR) energy users, and to highlight literature relevant to countries participating in the HTR Task by Users TCP by the International Energy Agency. Where available, we provide statistics and research from each of the participating countries (Sweden, Aotearoa New Zealand, the United States, Canada, and the United Kingdom), but we do not explicitly pursue comprehensive cross-country comparisons. This comprehensive literature review of over 870 publications focuses specifically on:
- Vulnerable households (including low-income and energy-poor)
- High-income energy users in the residential sector
- Renters and landlords in both the residential and commercial sectors
- Commercial sub-sectors that are HTR, and particularly,
- Small to medium enterprises (SMEs, also called small to medium businesses, or SMBs, in the U.S. and Canada).