Both types are designed to stand up to snow loads and provide protection against falling objects. Tempered glass breaks into small pieces, rather than large shards, if damaged. Laminated glass, which is fused with a thin layer of plastic, stays in place for added safety if broken. It's also better at keeping out sound and is slightly more energy efficient, though also slightly more expensive. Many skylight manufacturers offer an outside pane of tempered glass with an inside panel of laminated glass.
Skylights are also available with plastic glazings.
Plastic is less energy efficient than glass, but it costs less and can be formed into domes and curved skylights. The lowdown on leaks. The moist air inside your home collects in skylights and condenses on the underside of the glazing during the winter in most regions. On older skylights, this condensation is often mistaken for a leak as it drips back into the living area. A channel on most current models collects condensation so it can evaporate.