A dark tank inside a glazed, insulated box; simpler than a thermosiphon system, at some cost in overnight heat retention.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
A south-facing roof or ground area for the integrated tank/box
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.