Skylights are usually terrible because they heat the most at midday (when it's already the most hot) whereas conventional windows heat the most at dawn/dusk when it's colder.
Skylights also suck because they're exposing the window directly to the sky (and thus rain), whereas conventional windows are somewhat protected by eaves and the fact that the window is vertical so water can't pool on it.
Skylights also suck because they're exposing the window directly to the sky (and thus rain), whereas conventional windows are somewhat protected by eaves and the fact that the window is vertical so water can't pool on it.