Today, buildings still account for almost half of the global energy consumption and carbon emission. This highlights the necessity to increase energy efficiency requirements worldwide in a common effort to reduce the construction sector's impacts on the environment. The current energy policies are driving toward a design that relies on airtight and highly insulated envelopes. As a consequence, energy efficient houses are found to have insufficient indoor air change rates, impacting on the indoor air quality and resulting in higher latent loads.

Assessing the extent of evidence available relating to the impact of solar energy for households (HHs) in developing countries, surveys are reviewed focusing on the impact of pico‐photovoltaic (e.g., solar lanterns) or solar home systems (SHS) on rural HHs and directly related economic activities of their occupiers. Ninety‐eight documents have been analyzed. Areas of enquiry have included the impact of small individual solar photovoltaic systems on different facets of the life of HHs' occupiers: their education, health, finance, livelihoods, and social relations.

This report is the first report of the ‘Energy Savings 2030’-project which seeks to help the Coalition for Energy Savings to produce a robust and timely input to the 2030 policy discussion. It brings together and summarises recent empirical evidence on costs and benefits of energy efficiency measures. The evidence gap in terms of reliable ex-post data is well known. In the majority of cases results from ex-ante modelling studies inform the debate. The research carried out for this report confirms the persistent gap in publicly available ex-post evaluations of energy efficiency programmes.