Before getting into the why the usage of awnings, let us talk about what they are. Awnings are a projection over doors and windows. They are not a full roof / ceiling, but more of a quick construction to offer a sort of roof over doors and windows. They are constructed of different materials like canvas, metal, wood, and heavy duty screens. They also come in two styles, one is a permanent structure, where once it is installed it stays fully erected at all times. The other is a retractable, where the awning can be rolled up during times when a protection over the door or window is not needed.
Awnings have several different uses from aesthetic to practical. When an awning is over a window, normally it is there to block out the sunlight and or harsh weather elements. Normally the ones over windows are a permanent fixture, especially if it is a window that is rarely raised. Retractable types can be placed over windows, if the person desire to have more direct sunlight streaming into the room. Awnings over windows like that helps to preserve damage from UV light on the interior and helps to keep the windows cool in the hot summer months.
Awnings over doors often serve to protect against the elements of the weather, much like a covered or roofed porch or patio would. They exist like this strictly for keeping rain and snow, etc off of people as they enter into the home more so than protecting from sunlight. The added benefit though is that the awning over a door way will also shield from the UV light and thus the door will be cooler in the summer months, helping to save and conserve energy by keeping the air cooler on the inside of the home.
Awnings are as decorative as they are practical and many use them to give the home a cozy cottage feel. They are created to match the exterior of the home and add visual curb appeal as well. Larger ones can be placed over patios and decks, and even more useful are the retractable type that can be scrolled away if blockage from the sun or rain are not needed. These add a safe place in the yard and look good too, creating an escape from harsh weather, mainly from direct UV light. They are perfect for barbecues and cookouts.