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?
Insulated operable shutters
Passive
One of 6 ways to meet this need. Cost, carbon, footprint and rankings are relative to other solutions for the same need, not absolute.
Removable or foldable insulated panels over glazing at night, cutting heat loss when the sun isn't providing gain anyway.
20-30 years for hardware/hinges; insulation core inside the panel matches the insulation material used
Embodied carbon
Low
Space / material use
Low
Output timing
On-demand/controllable
Skill to repair
Basic
Regulation (FR example)
Changing the external appearance of an existing building normally requires a prior declaration (declaration prealable) at the mairie; stricter rules and an architect consultation apply within a protected or heritage perimeter.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Insulated operable shutters (This page) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: Regular · Change to daily life: Daily · Works without the grid: Yes Choose it if you want the strongest night-time insulation over the glass for little money.
Triple-glazed, low-E windows Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: High · Skill to build: Intermediate · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want the windows that keep the most heat in.
Double-glazed windows, insulated frames Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: None · Change to daily life: None · Works without the grid: Yes Choose it if you want most of the gain of new windows for a lower price and weight.
Secondary glazing (retrofit inner pane) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: None · Upkeep: Light · Change to daily life: Daily · Works without the grid: Yes Choose it if you rent, or must keep your old windows, and want a cheap extra layer.
Electrochromic (smart) glazing Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: High · Skill to build: Specialist · Upkeep: None · Change to daily life: None · Works without the grid: No Choose it if you want each window to let the sun in or keep it out at the touch of a switch.
Insulated draft-blocking curtains 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: None · Works without the grid: Yes Choose it if you want to stop draughts at the window with something you can sew yourself.
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.