Built heritage has an important role in the development of the global tourism industry. Therefore, appropriate conservation methods are required to support cultural identities and the tourism industry. Within the Sistan region of Iran, there are a number of built heritage assets (such as castles) that were constructed in different periods of history. Due to climatic conditions, management issues, and unemployment issues, ineffective conservation measures have been implemented for these types of built heritage assets. Therefore, special conservation methods are required to address different performance issues. This study offers practical solutions for the conservation of Sistan’s castles. An eco-sustainable model is proposed as a method to plan appropriate conservation interventions that consider economical, ecological, and labor-friendly characteristics of sustainability. We demonstrate that this approach to architectural conservation is responsive to local constraints and can be compatible with local requirements.