The answer to 'skylight or skylight' is that skylights and roof windows are both types of overhead windows that allow natural light into a home, but they have some key differences in terms of features, benefits, costs, and use cases. Skylights are fixed windows that are installed directly into the roof, while roof windows are operable windows that are hinged at the top and can be opened to allow ventilation.
Skylights generally provide more natural light than roof windows, as they are typically larger and have less framing. They can also help to reduce energy costs by allowing you to use less artificial lighting. Roof windows, on the other hand, offer the added benefit of ventilation and can be used as an emergency exit in some cases. Roof windows are also often easier to install and maintain than skylights. In terms of cost, skylights tend to be more expensive than roof windows, both for the initial installation and for any necessary repairs or replacements.