Skylight / July 11, 2018 / Nicolas Charlebois
You will need to position and mark the opening on the ceiling after the skylight is installed. Take into consideration the size of the room and the amount of light you wish to bring in and select the size and position of the hole accordingly. Once the skylight is installed and the ceiling hole is cut its then a matter of connecting the two with the shaft which is typically constructed from 2x4 or 2x6 lumber. The angles involved typically require some tricky framing and is probably best left to an experienced carpenter. After the framing is completed the inside of the shaft is covered with wood or drywall and the attic side is insulated to minimize heat loss.
For one thing skylights are positioned in such a way that they are inaccessible unless they are operated by remote. Even in cases of motorized skylights which are easily manipulated there are still some disadvantages that are inherent to skylights that are not present or minimized in windows. Vertical windows lose less heat by convection when compared to skylights. Also since windows are generally protected by overhangs or shrubs they lose less heat by radiation. On the other hand skylights are directly exposed to the sky. Thus they lose more heat by radiation. Proper insulation can reduce this heat loss to a large extent. In the summer season skylights are more exposed to the direct heat of the sun than windows.
For example the optimum slope for a south-facing skylight in Columbus Ohio at 40º North latitude is 45º to 55º. Every skylight has a "shaft" which governs how much light is admitted into the room below. If all four sides are flared then the light is spread over a wide area. If your skylight has a shaft with perpendicular sides the light is focused straight below. If your skylights shaft is flared on only one or two sides then the light is sprayed in the flared direction. Ventilation If you wish you can have a skylight which also provides ventilation as well as light to your room. This allows you to release the hot air which collects at your ceiling.