Passive convective loop between a collector and an elevated tank; no pump or electricity needed.
Note: Cost, carbon and footprint are rated against the other options for this same need, not in absolute terms.
A south-facing roof or wall area for the collector, and a tank position above or level with it for thermosiphon flow
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.