The installation of roof windows (or roof lights) will allow light to flood into the space within. Light from rooflights can be of higher quality than light delivered via vertical windows in walls.
Therefore if you have a sloping ceiling within your room and you wish for more light then consider a roof skylight rather than punching a hole through a wall for a standard window. Installing a roof window is easier with the minimal of damage and disruption.
Why Roof Lights
Roof windows are a great way of providing additional natural light to a space within. Roof windows are the perfect choice where conventional vertical windows cannot be installed or if there are planning issues. Quite often roof windows are installed in attic conversations.
Roof windows from the outside have a low profile, unobtrusive and therefore fit in well with the character of the building. Compare this to dormer windows which can be quite ugly, the roof requires strengthening and will probably require planning permission. Roof lights may not always require planning permission.