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?

Daylight-factor window sizing and placement

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.

Deciding the size and position of each window from how much daylight each room needs, rather than from habit. A simple calculation shows where light will fall and how deep it will reach. Rooms get enough daylight, so electric lights stay off for more of the day.

Cost

Low

Upkeep

None

Skill to build

None

Lifespan

Matches glazing lifespan (a sizing/placement calculation, not a separate material)

Embodied carbon

None

Space / material use

None

Output timing

Weather/time-dependent

Skill to repair

None

Inputs

• Solar radiation

Outputs

• Daylight

Compare the 2 ways to meet this need

Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.

• Daylight-factor window sizing and placement (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 want enough daylight in every room, planned rather than guessed.
• Motorized heliostat mirror (north-facing daylighting)
  Can I use it? Works in a flat · No rebuilding needed
  What does it cost me? Upfront cost: Medium · Skill to build: Specialist · Upkeep: Heavy · Change to daily life: None · Works without the grid: No
  Choose it if you want sunlight in a north-facing room that never gets any.

Sources

• EN 17037:2018+A1:2021 "Daylight in buildings", clause 5.1 and Annex A (daylight provision: a target illuminance of 300 lx over half of the room for at least half of the daylight hours). Standard, not freely available

Limitations of this page

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.