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?
Double-glazed windows, insulated frames
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.
Windows with two panes of glass and a well-insulated frame. The layer of still air or gas between the panes slows heat escaping. They are a big improvement on single glazing, and cheaper and lighter than triple glazing.
Build it
This solution is not buildable as a DIY project.
Cost
Medium
Upkeep
None
Skill to build
Intermediate
Lifespan
20-35 years, same sealed-unit failure mode as triple glazing
Embodied carbon
Medium
Space / material use
Low
Output timing
None
Skill to repair
Intermediate
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.
Double-glazed windows, insulated frames (This page) 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.
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.
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.
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.
Sources
Glazing industry lifespan sources (Glass & Glazing Federation guidance via Everest/Gowercroft consumer glazing sites)
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.