What Do We Understand by a Roof Window?

A roof window is an opening casement that opens outwards. It comes
incorporated and attached as a part of the roof design. The shape, design, and
other features and attributes of the structure can vary according to the various
needs, preferences, and requirements. Nonetheless, the overall purpose of a
roof window is to allow a sufficient amount of fresh air and sunlight to enter
unrestricted and unobstructed from above into a particular space. 

What Do We Understand by a Skylight?

A skylight is an opening structure on the roof space that resembles a roof
window. However, the two have substantial differences between them. In
general cases, the light-transmitting casement of a skylight are made of a
translucent or transparent material such as glass. It gets constructed primarily
for the purpose and necessity of ventilation and daylighting. A skylight is also
known as a roof light. 

What are the Various Points of Differences between a Roof Window
and a Skylight?

The structures and purposes of a roof window and a skylight are similar in
various aspects. However, the two have a few disparities that make it evident
that they are distinct structures and not the same. These differences between
the two consist of the following:

Size

In most cases, a roof window has a broader area and size. It stands true
compared to a skylight. It allows for an extensive view and scene of the sky and
objects above the room or hallway where the former structure gets installed. 

Opening Feature

Typically, a roof window is like a traditional window. In other words, the
casement has features and functions that allow it to open in one direction to a
specific extent. It allows for the entrance of fresh air. On the other hand, a
skylight has no such elements. It remains fixed in place and cannot get opened
in any direction.

Covered Space

A skylight covers a significant amount of space in its place of installation and
construction. The covered area for a roof light is comparatively much less.
Thus, the former is a better choice. It is so for hallways and rooms in buildings
that rely on daylight to work.  

Cost

The cost of a skylight is more than a roof window. It is due to the higher
expenses for the installation, construction, safety measures, and other
elements for the former. 

Roof Pitch and Versatility of Installation

A roof window requires a particular degree of roof pitch to get installed.
Generally, it stands at about 15 degrees at the minimum limit. This
requirement does not arise for a skylight. It can get installed on even a flat roof
with no roof pitch. In addition, a skylight has a versatile installation. It can get mounted or fixed
or a curb. This setup type provides the structure with more options during the
fixing and fitting process. On the other hand, a roof window requires the same
plane and orientation as its surrounding roof.