In a renovation on the other hand we have to consider what effect a new skylight will have on the efficiency of the existing building. In some cases the additional sunlight (and therefore heat) can help reduce the amount of energy needed to heat the house. It depends greatly on the local climate but also on the design of the building envelope of the house.
A skylight is like a window on your roof. Simple skylights can be used to bring extra light to a room as a substitute for artificial lighting throughout the day. More complex skylights can even offer an access point for roof maintenance (ideal for checking up on a green roof for example). Skylights can be fixed vented tinted or even combined with an automated shutter system and can include a fly screen. A light tube on the other hand is good for rooms that don’t have a ceiling at roof level. It’s basically a reflective pipe that bounces the daylight down to the room where it is needed. Light tubes can be combined with lighting fixtures so the same area that lets in daylight during the day can double as a light for the evening.
The most common use of up lighting is in a recessed cove around the top perimeter of a room. To maximize light output use a T5 fluorescent or LED light source that will wash the ceiling with light. This helps to create a brighter ceiling that bounces and reflects light throughout the space without glare. Combine this with lots of natural daylight to increase the overall light levels in a room.