For historical and demographical reasons, in many European countries, an important part of educational building must be retrofitted. These retrofitting must be carried out in a context of reduction of greenhouse emissions and energy consumption.Among different targets for retrofitting, there are the improvement of indoor environment. In fact, educational buildings are particularly vulnerable to indoor environment problems. Studies have indicated a correlation between the way educational buildings are designed, or retrofitted, and student performance. Studies were complicated by the highly systemic nature of education and the range of social, pedagogical and environmental variables involved.In this study, special aspects of retrofitting educational buildings are set out, and indoor environmentrequirements are presented. Then, people satisfaction, regarding the indoor environment in four refurbished buildings are studied with an enquiry with provides questionnaires. This includes air and ventilation, heating and temperature, daylight and lighting, sounds and noise, cleanliness and comfort and health aspects.