DIY window curtains built from an outer fabric layer and an inner reflective/insulating layer (e.g. mylar or foam-backed material), sealed to the window frame with velcro to cut air infiltration and radiative loss, a soft-goods, easily-retrofit alternative to the rigid insulated shutters: faster to make and hang, no structural fixing, but less airtight and less insulating per unit thickness than a solid panel.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
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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.