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.

Background
In 2007, the Indonesian Government instigated a national program to convert domestic kerosene users to liquefied petroleum gas (LPG) for cooking. This was primarily motivated by the rising cost of kerosene subsidies.

Objective
To review the national conversion program and LPG scale up by evaluating its impacts, including assessing sustained changes in cooking behaviour and consequent reductions in exposure to household air pollution (HAP).

This study presents three cost-optimal calculations. The overall aim is to provide a deeper analysis and to provide additional guidance on how to properly implement the cost-optimality methodology in Member States. Without proper guidance and lessons from exemplary case studies using realistic input data (reflecting the likely future development), there is a risk that the cost-optimal methodology may be implemented at suboptimal levels.