Very few windows are manufactured with security in mind. Most windows are designed for aesthetics and energy efficiency.
Basement windows are extremely vulnerable and offer virtually no resistance to forced entry. The typical basement window is held in place by two spring-latches. Applying small amounts of direct force to this type of window will cause it to fall out of its frame.
Security can be improved by installing bars or glass blocks in basement windows. While increasing the security of the residence, bars and glass blocks can restrict occupants from escaping the residence during a house fire. This should be considered prior to installation.
Single or double-hung windows are also difficult to secure. Casement windows offer a better form of security. When considering windows as replacements or during construction of a new home, ask whether the window unit meets or exceeds the American Standard for Testing and Materials (ASTM) F 588-85. Windows meeting or exceeding this standard have been tested for their ability to resist forced entry and are a step up from the typical builders-grade window unit and may be expensive.
Laminated glass should also be considered to enhance the overall security of these window units. This type of window will not sacrifice aesthetics to enhance the overall security of the home. The ability to get out of the house in the event of fire is not compromised for security purposes.