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?
South-facing glazing sized for winter gain
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
A genuine south-facing aspect available on site
Windows on the south side, sized and placed to let in the winter sun. The sun is low in winter, so its light reaches deep into the rooms and warms them for free. Planned well, these windows take a real share off the heating bill.
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 glazing lifespan (a sizing/placement choice, not a separate material)
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
South-facing glazing sized for winter gain (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: None · Works without the grid: Yes Choose it if you are building or replacing south windows and want a real share of the heating for free.
Slate-clad solar air heater (wall-mounted thermosiphon collector) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Basic · Upkeep: Light · Change to daily life: Occasional · Works without the grid: Yes Choose it if you want to warm one small room on sunny winter days with a box you can build on a south wall.
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.