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?
Improves the thermal performance of a window, door or glazed area, whether by replacing it, adding a layer to it, or covering it at night. The opening is the subject; if the row would apply to a blank wall it belongs elsewhere.
Ranked by U-value, how much heat the whole unit loses per square metre for each degree of difference between inside and out, so lower is better. Triple glazing with a low-E coating is the ceiling; each step down adds either a pane or a night-only layer. Note shutters and curtains work only while closed, so they cut night-time loss without improving the window itself.
Solutions
Triple-glazed, low-E windows: Windows with three panes of glass, the gaps between them filled with still gas and the glass coated to reflect heat back inside. Each layer slows the heat escap
Double-glazed windows, insulated frames: 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 s
Secondary glazing (retrofit inner pane): Traps a still-air layer against an existing window instead of replacing the window. The considered version is a second pane held in a frame inside the reveal, i
Insulated operable shutters: Removable or foldable insulated panels over glazing at night, cutting heat loss when the sun isn't providing gain anyway.
Electrochromic (smart) glazing: Glass that darkens or clears at the touch of a switch, through a thin electrical coating between the panes. It can block the summer sun and let the winter sun i
Insulated draft-blocking curtains: 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