Over the past two decades, the construction industry has prioritised sustainability, focusing on reducing emissions and improving energy efficiency. 

While new buildings can easily implement these practices, most of the built environment consists of existing structures, many of which were built before modern environmental standards. 

Historical buildings, like churches, are particularly challenging due to their historical significance and architectural uniqueness. Efforts to align them with sustainability goals often involve minimal regulations, which can harm their usability and conservation. 

This article explores energy efficiency challenges in three churches in central Poland, analysing their architecture and proposed energy-saving measures.