The Quest for an R15 Thermal Window Shade

Back in the late 70's and 80's there was an effort to develop very good insulating window shades.  These shades used multiple layers of reflective plastic films to achieve very high R values.  Some of the shades were reported to have R values in the R15 area, making them as good as a typical insulated wall, and cutting window heat loss by a factor of 7 over a conventional double glazed window.

With the end of the oil crisis in the 80's, work on these shades stopped, and  (as far as I know)  the commercial products that were coming out went away.

I think that this is a very promising area for development, and well within the capability of many backyard inventors and experimenters.  It is a promising area for both DIY and commercial development.

Heat loss from windows can be as high as 50% of the total house heat loss (depending on the house design), so cutting this to near zero with these shades could be a significant reduction in fuel costs and greenhouse gas emissions.

One example includes 3 transparent layers that can be deployed separately for various winter and summer scenarios.  It also has a very tight edge seal design.

A 2nd example uses 5 layers of reflective material to achieve very high R values.  All 5 layers roll into a 2 3/4 inch diameter roll.

The third example uses 4 layers of reflective material in a configuration that "self inflates" when down to achieve spacing of the layers.  The shade rolls up on a 3 inch diameter roller when deflated.

The 4 page excerpt in pdf ...

The various materials used for each layer are discussed.  Testing that compares the performance of these muli-layer shades to various types of conventional insulation is provided.  The performance of the shades was found to be comparable to 4 inches of fiberglass insulation!

The 3 page article in pdf ...