The company says the tri-pane glazing option for its Wood-Ultrex casements and awnings is its most energy-efficient to date. Made with three panes of glass and argon gas, the windows have U-factors of 0.18 to 0.20. They also have a design pressure rating of 50 and come in standard and special sizes. Cost: $430 to $900. Integrity Windows and Doors. 888-419-0076.www.integritywindows.com.