Movable Insulation Jennifer Durham

 Usually insulation is used inside walls, ceilings, and floors to trap heat and create a thermal envelope.  Windows penetrate the envelope, letting the heat escape

 A versatile window covering that allows beneficial heat gain during winter, and minimizes unwanted heat gain in summer.  Simple examples: insulative shade, shutter panel, or curtain.

 R-value measures resistance to heat gain or loss. A typical insulated wall has an R-value anywhere from 12 to 19, while a double-pane window has an R-value of about 2. By using movable insulation within the window frame, the R-value nearly doubles. This reduces overall heating and cooling load.

South-facing windows are the most beneficial for providing heat. East and West windows are most beneficial during the spring. They loose heat during the window, where insulation is necessary. North facing windows are always heat losers, so insulation is necessary.

 The advantages of interior insulation are protection from the weather and simplicity of operation. Examples are thermal curtains, shades, shutters, and window quilts. Shades and shutters keep out (or retain) the most heat, but also cost more than curtains and window quilts. Shades are most effective if they are properly sealed along the edges of the window. Interior shutters are usually made of polystyrene or a foam sheathing encased in wood or metal, and can triple the R-value of a window.  Exterior shutters are used less than interior. They can reflect more sunlight into a home during winter months. They also do a better job of reducing solar load in the summer, but generally cost more than interior insulation, and are subject to constant weathering.

Because cool air tends to fall to the floor, the bottom seal on a curtain is most important. Flexible, easy to operate

Used for North facing windows in the winter Larger and heavier than insulation designed to be used everyday, and has more insulation

 The edge seals are made to butt with a foam gasket  Easy to operate

Three separate shades for windows and glass patio doors. It is made with a reflective film shade on the window side, a clear film shade in the middle, and a black, heat-absorbing film shade on the room side.

 Used as reflectors to boost solar heating gains on winter days.  The change in the orientation of the sun make them useful for only a couple hours each day

External shutters operated from interior

 Darling, David. “Movable Insulation.” The Encyclopedia of Alternative Energy and Sustainable Living. 16 January  Langdon, William K. Movable Insulation. Rodale Press