Secure double-hung sash windows by drilling a hole that angles downward through a top corner of the bottom window into the bottom corner of the top window on both sides of the window. Place an eyebolt or nail in the hole to prevent the window from being opened. Replace louver windows with solid glass or some other type of ventilating window. If this cannot be done, glue the panes together with a two-part epoxy resin. Secure casement windows with key-locking latches. Make sure that the protrusion on the window that the lock is attached to is made of steel and not worn, and that the window closes properly and is not bowed or warped. Secure sliding-glass windows as described above for sash windows or by the same types of locking devices used for sliding-glass doors. Consider installing security bars on side, rear, or other windows that a burglar might break to enter your home. Make sure that the retaining bolts cannot be removed from the outside. Bars must comply with Fire Code requirements for inside release to permit an occupant to escape in the event of a fire. Reinforce the glass in viewing windows on the lock sides of doors so a burglar cannot break them and reach in to open the door.