Removable or foldable insulated panels over glazing at night, cutting heat loss when the sun isn't providing gain anyway.
Cost
Low
Upkeep
Frequent
Skill to build
Basic
Lifespan
20-30 years for hardware/hinges; insulation core inside the panel matches the insulation material used
Embodied carbon
Low
Space / material use
Low
Output timing
On-demand/controllable
Skill to repair
Basic
Regulation (FR example)
Changing the external appearance of an existing building normally requires a prior declaration (declaration prealable) at the mairie; stricter rules and an architect consultation apply within a protected or heritage perimeter.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
Inputs
none
Outputs
none
Sources
General exterior shutter-hardware industry durability consensus
What this page does not tell you
No sizing or quantities: how much a technique yields, and how much a household needs, both depend on the build and the people, so the catalogue compares options rather than dimensioning them. It carries no bill of materials and no build sequence, and it is written for an oceanic, clay-soil climate (Normandy, France). Regulatory notes are indicative and need confirming locally.