Impact windows are thicker and much heavier than standard double-pane windows; they have heavy-duty aluminum frames to support them in hurricane-force winds. It’s a challenge to handle the additional weight of these windows.
Unlike other windows, it’s extremely important to be sure they are leveled after installation. They have a large number of screws to secure them in place, to make sure they hold up against hurricane winds. The screws used must be in code as well and are longer and thicker than standard fasteners. The closer the building is to the coast, the more screws will be used in the installation process.
Windows must have a tight fit with proper sealing around frames to keep the water out. Caulk and flash stripping are used to keep frames and windows as watertight as possible.
If you’re replacing old windows with impact windows, keep in mind that removing old windows can be tricky as well, and dry fitting steps should be performed. Any deviance from manufacturers’ installation requirements will void the product’s warranty and impact the windows’ effectiveness.