Natural Home Day-Lighting: Windows, Clerestories and Skylights

Natural Home Day-Lighting: Windows, Clerestories and Skylights

Natural day-lighting is a strategy of placing windows, skylights, clerestories and sunrooms and other transparent media in order to bring sunlight into home, providing a better indoors illumination and reducing artificial lighting and fossil energy consumption.

You should consider natural day-lighting as part of your global approach for building an energy-efficient home.

In order to implement day-lighting you should locate and dimension your windows correctly. And eventually bet on skylights, clerestories and consider sunrooms...

Advantages of south-facing windows

South-facing windows (or north facing windows, in case you live in the south hemisphere) are highly advantageous for day-lighting: they allow most winter sunlight into the home; and if the building is properly shaded they will not cause too much sun during the summer.

Advantages of north facing windows

North-facing windows (or south facing windows if you live the south hemisphere) have some good advantageous for day-lighting: they admit natural light and little glare (and little heat gain in summer). These windows should not have large dimensions, to avoid undesirable losses of energy (in winter).

Advantages and disadvantages of east and west windows

East and west facing windows are good elements of day-lighting in the morning and evening respectively, but their number and dimensions should be limited. They are cause of glare and they admit too much heat during the summer and do not contribute significantly to solar heating in winter.

Clerestory windows

Clerestory windows are high, vertically-placed windows. Clerestories may provide light to rooms that otherwise will not be illuminated (north-side rooms in the northern hemisphere; and south-side rooms in southern hemisphere)

Clerestories are also used to admit diffuse day-light (from the north, if you live in the northern hemisphere; from the south if you live in the southern hemisphere) in rooms demanding balanced day-light.

Clerestory are also often used to allow light onto interior wall surfaces. These walls should be painted with a light color (preferably white) in order to reflect indirect light to interior areas, reducing shadows and making a softer illumination.

Clerestories should be placed or shaded correctly, since they may be a cause of undesirable glare and heat when facing toward the sun.

Skylights

Skylights may be an excellent element of natural day-lighting strategies, but they should involve good glass (at least two panes glass) with a heat reflecting coating. You should demand high energy efficient skylights. Otherwise they will be cause on unwanted heat or cold losses. Skylights should also be properly installed and constructed to avoid leak and condensation problems.

As a piece of natural day-lighting, skylights shouldn't represent more than 1-10% of floor area (depending on climate, latitude and design).

Advanced skylights may use domed shapes and other light-redirecting glazings to allow superior even light levels.

Skylights can also be used with shade trees, located in strategic locations - to prevent too much heat or light to enter into the house.

See, for details: Basics on Skylights

The importance of energy efficient windows, clerestories and skylights

Today's energy-efficient windows (including skylights and clerestories), well dimensioned and located, reduce the need for artificial lighting during daylight hours, while reducing heating and cooling costs.

Energy efficient windows are an essential element of daylight and energy efficiency: without advanced windows the gains in day-lighting may well be lost via undesirable heat or cold...