Since they’re using French for the rating, I’d think the shutters improve the score and that contributes to their pervasiveness.
From a quick search, older versions of the DPE ignored shutters, modern ones take them in account and their effect ranges from neutral to positive depending on details (materials, insulation, fit). It’s not entirely clear if both high seasons are considered (insulation and fit I’d think a lot less critical in summer).
From a quick search, older versions of the DPE ignored shutters, modern ones take them in account and their effect ranges from neutral to positive depending on details (materials, insulation, fit). It’s not entirely clear if both high seasons are considered (insulation and fit I’d think a lot less critical in summer).