Passive
One of 2 ways to meet this need. Cost, carbon, footprint and rankings are relative to other solutions for the same need, not absolute.
An accessible flat outdoor surface with clear sky to the south for most of the day, and a building prepared to allocate it. The second is the real prerequisite: the technical bar here is nearly nothing and the collective decision is the whole of the difficulty
A communal terrace or flat roof given over to solar equipment that the households below have nowhere to put: a parabolic cooker, a solar oven, a dryer. The point is not the equipment, which this catalogue lists on its own rows, but the arrangement. Solar cooking needs an unshaded place to leave something standing for hours, and that is precisely what a flat lacks, however well it faces. One shared surface supplies it to every household in the building at once, and splits the cost of kit that none of them would buy alone. It is the clearest case in the catalogue of a solution that only exists at the scale of the building rather than the home.
Nothing separate is built here: this is a choice about how the home is designed or used.
none
none
Compare building and maintaining complexity, as well as efficiency where possible.
| Solution | Build skill | Upkeep burden | Efficiency |
|---|---|---|---|
| Open-plan shared living/kitchen/dining | None | 0 | N/A |
| Shared solar terrace | None | 2 | N/A |
Build skill and upkeep burden are proxies (lower burden = simpler to maintain); the efficiency column is this sub-function’s ranking, 1 = best. “N/A” where an axis isn’t rated here.
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.