Lowtech Graph lists low-tech options for every need of a home. Here you can compare them, find tutorials to build them, and link them together into a circular system. Why low-tech?
Cross-ventilation (opposed openings)
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.
What your site needs
Openings on at least two opposing or near-opposing facades
Openings on opposite facades let prevailing wind drive airflow with no power input.
Build it
Nothing separate is built here: this is a choice about how the home is designed or used.
Cost
Low
Upkeep
None
Skill to build
None
Lifespan
Matches opening/window lifespan (a strategy using standard operable windows, not a separate component)
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Cross-ventilation (opposed openings) (This page) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: None · Upkeep: None · Change to daily life: Occasional · Works without the grid: Yes Choose it if the wind can reach windows on opposite sides and you want free ventilation.
Stack-effect / solar chimney ventilation Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: Light · Change to daily life: Occasional · Works without the grid: Yes Choose it if you want ventilation with no fan, even on still days.
We don’t list sizing or quantities, as the yield of each technique depends on the quality of its build. The catalogue compares options but doesn’t dimension them. Regulatory notes are indicative, with a French example, and need to be confirmed locally.