Fenestrations are glazed apertures in buildings. These include conventional windows, roof skylights, glassed doors, clerestories, roof monitors, tubular skylights, and sloped glazings of different kinds. 

Fenestrations are normally placed in buildings to provide a view of the outdoors and for the admission of daylight illumination to the interior. Along with these generally desirable features come solar radiant heat gain (generally desirable in winter and undesirable in summer) and conductive heat transfer. The latter adds to the cost of heating the building in winter and cooling it in summer. The daylight illumination, while generally desirable, can also be a source of unwanted glare. The solar heat gain accompanying it can induce occupant discomfort as well as increased air conditioning costs. Click here for more information on UV Transmittance & Fading of Interior Furnishings.

Designing, orienting, shading, and sizing windows to increase their benefits while reducing problems (glare, overheating, condensation, cold draft, large heating or cooling loads, furniture fading) is an important goal of the building designer. If the original design is not good in these areas, occupants may experience problems. 

Retrofitting improved windows, shades, or other attributes can cost a lot.  However, replacing old conventional windows with well-chosen energy-efficient ones can result in significant yearly energy savings, better comfort, and improved occupant satisfaction. While desirable in residential buildings, this can also increase productivity in commercial or office buildings.  Often the productivity enhancements save more dollars than the entire energy bill itself!

There are important human factors and energy aspects to window design, placement, and sizing. In the past, when the variety of available window designs was limited in a given climatic region, the selection of an appropriate window design was a relatively easy task.

Now, however, the greater variety of products and design strategies, coupled by varying needs of people in different locations and climates, makes the design of fenestration systems more involved and complicated.

How Windows Work Designing, orienting, shading, and sizing windows to increase their benefits while reducing problems (glare, overheating, condensation, cold draft, large heating or cooling loads, furniture fading...) is an important goal of the building designer.

The Window Market Modern energy-efficient windows can be tailored for hot or cold climates, lowering energy bills and increasing comfort and view as well. No longer are heavily tinted windows needed to provide good energy performance in the south. No longer do northern residents have to put up with condensation on the panes or frames.

Solar Lighting A variety of solar daylighting systems can be used for lighting the interiors of buildings. Some are designed to introduce sunlight to the perimeter spaces, or to the top floor of a multistory building. Others target the interior spaces of multistory buildings.

Slide Shows Here is a list of fenestration related slide shows. By clicking on their links you can view these slide shows in pdf form.

Window Links Here is a list of windows & daylighting (fenestration) related links. By clicking on the links you can view each Government, Research, Educational, Professional or Trade Organizations associated with the fenestration process.