This contribution proposes a comparative analysis of how legislation on built heritage protection and regulations on energy demands affect current 19th century housing buildings in the city of Geneva. Four measures of protection are analysed, looking at how comfort legislation and heritage protection come together in the recent renovation of roofs, walls and windows. The aim is to identify possibilities for good compromise or possible conflicts when renovating these elements in current 19th century housing ensembles. Their key value – which might sometimes be disregarded – often lies in the repetition of proportion, layout and detail, forming ensembles that contribute to the definition of urban identity in many cities.