The biggest news in window technology is “low-e” films for low-emissivity. These thin metal coatings allow the shortwave radiation of solar energy to pass in, but block most of the long-wave thermal energy tying to get back out.
Low-e films block most solar heat gain while transmitting most visible light. Windows treated with low-e film help in both the winter and summer, with little heat leakage coming inside on a hot summer day, or leaking outside in winter.
A low-e coating is virtually invisible from the inside, but most brands tend to give windows a semi-mirror appearance from the outside.
Low-e windows are available ready-made from the factory, where the thin plastic film with the metal coating is suspended between the glass panes, or, low-e films can be applied to existing windows.
Excerpted from the Real Goods Solar Living Source Book, edited by Doug Pratt and executive editor John Schaeffer.Copyright (c) 1999, Real Goods. Reprinted by permsision of Chelsea Green Publishing Company and Real Goods.
Excerpted from Real Goods Solar Living Source Book,edited by Doug Pratt and executive editor John Schaeffer.