This paper reviews empirical data from evaluations of the influence of residential energy efficiency retrofits on indoor environmental quality conditions and self-reported thermal comfort and health. Data were extracted from 36 studies described in 44 papers plus two reports. Nearly all reviewed studies were performed in Europe or United States. Most studies evaluated retrofits of homes with low-income occupants. Indoor radon and formaldehyde concentrations tended to increase after retrofits that did not add whole-house mechanical ventilation.

Improving energy efficiency has long been advocated as a way to increase the productivity and sustainability of society, primarily through the delivery of energy savings. The impact of energy efficiency measures can go far beyond energy savings, and energy efficiency improvements can be an important contributor to economic growth and social development.

The untapped / hidden benefits of environmental policies are huge, this piece of research showcases and places a monetary value on the added benefits to our health, society and the economy that environmental investments and policy linked to energy efficiency can bring. Findings show that green policies can improve both our health and the economy and can go hand-in-hand. This study provides guidance to policy and decision-makers in developing a methodology for the inclusion of multiple benefits in a cost/benefit assessment of energy efficiency policy.

The review of policies being implemented in China, the EU, India and the US presented in this report has also identified some key challenges that we must address if we are going to realize the mitigation potential of the building sector. Chief among these is the need to improve our monitoring of the impact that our policies are having. Lack of measured and verifiable data on the influence of policies on building energy performance currently hampers our ability to assess and continuously improve their effectiveness.