Cool Stuff

Sunlight- and temperature-sensitive windows from Denver-based Ravenbrick automatically darken on hot, bright days to block sunlight from a home's interior. On cool days, the windows stay clear to admit sunlight and allow solar gain. Although not yet available for residential application, the technology should add about 30 percent to the cost of a window and pay for itself in reduced energy bills within six years.

Spot-reducing titanium-dioxide coatings are supposed to reduce water's ability to organize itself into droplets that create spots and streaks. These self-washing windows are available from a few manufacturers, including Andersen.

Tilt-and-turn windows, popular in Europe, may soon be introduced into the U.S. market. These unique windows can be opened two ways: With a side hinge that lets the sash swing horizontally and with a bottom hinge that permits the window to be opened like an awning window. The dual-action offers interesting flexibility for cleaning and for interior design.