How do you stop heat loss through windows in a home?

Windows are the worst energy leakers you can ever have in any house. Natural light is great but it comes at great cost. They let too much heat inside in the summer and too much cold inside in the winter. Doing anything is better than nothing. Just stretching plastic over them or hanging a blanket over them is better than doing nothing.

The best way to deal with it is to get the best Windows that you can and use a thermal barrier or shutter. There are attractive roll up thermal shades that are made of comforter or winter jacket like material (thinsulate, etc.). They are usually or shall I say best mounted on tracks to seal the window on cold nights or hot days. Some are manually operated (cranked up and down) and some are electrically operated. The advatage to these are the roll up storage. Cons are expensive and lower R values.

Mine are a rigid heavy sandwich type. I will be writing an article on my blog about them soon. They are 2" foam core (Owens corning formular 150 R-10) with thin white hardboard glued to each side. I live in a condo so it has to look like a shade or blind when viewing it from the outside. I left the inside facing board white (as my walls are white). You can however, paint it to match your walls or do a number of other treatments such as fabric or even put art or posters on it. Imagination is your only limit.

Advantage is the high R value (I will get an R12-15 with the air gap and high performance Windows). Disadvantage is weight and storage. I created one piece, no hinge "plugs" for my Windows. These are very heavy and clumsy to move on the big window. I have to store them behind book cases and the sofa when not in use. The advantage to this is fewer gaps and that means a greater seal and less heat loss. More convenient and attractive options are available.