Energy retrofit techniques: An experimental study of two typical school buildings in Tehran

• The retrofit procedure in two school buildings is studied.
• Energy consumption and indoor air quality are studied before and after refurbishment.
• Retrofit measures are selected by energy simulation and payback time analysis.
• The primary energy decreased 29% and 38% after refurbishment in the studied cases.

Energy retrofit of educational buildings is an effective solution to the high energy consumption and thermal discomfort problems in this sector. This article presents the retrofit procedure of two typical schools built before and after 2000 in Iran. The procedure contains three steps: first preliminary building performance assessment and presenting retrofit proposals, second optimizing and prioritizing scenarios based on energy simulation and payback time (PBT), and third assessment of the implemented techniques. Energy modeling and PBT analysis indicate air tightening, window replacement, and roof insulation are among the most efficient scenarios for implementation. The selected measures are implemented and the energy consumption and thermal environment of the schools were monitored in order to assess the energy target achievements. In addition to 29.87% and 38.29% primary energy reduction observed after retrofit implementations in the old and new cases respectively, questionnaire surveys approved indoor environmental quality enhancements. As a pilot study the results show that the proposed method could support the decision making process in future retrofit projects.