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 draft-blocking curtains
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.
Homemade curtains with an outer fabric and an inner reflective or insulating layer, sealed to the window frame with Velcro. They stop cold draughts and keep the warmth of the room from escaping through the glass at night. They are quicker to make than insulated shutters and fix to nothing, but insulate a little less.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Insulated draft-blocking curtains (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: 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.
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.
Insulated operable shutters 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.
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.
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.