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Daylighting — the method of using natural light to illuminate building spaces — is one of many green practices that electrical contractors can incorporate into their businesses in order to meet the rising demands of facility owners who are becoming more educated about sustainable building. By offering customers newer lighting technologies that allows them to attain greater levels of output with less cost, contractors can stay ahead in the green market.

According to the Whole Building Design Guide, the art and science of proper daylighting design is not so much how to provide enough daylight to an occupied space, but how to do so without any undesirable side effects. It involves more than just adding windows or skylights to a space. It is the careful balancing of heat gain and loss, glare control, and variations in daylight availability. For example, successful daylighting designs will invariably pay close attention to the use of shading devices to reduce glare and excess contrast in the workspace. Additionally, window size and spacing, glass selection, the reflectance of interior finishes and the location of any interior partitions must all be evaluated.

However, while a building can be designed for daylighting, without an integrated electric lighting system it will be a net energy loser because of the increased thermal loads. Only when the electric lighting load is reduced will there be more than offsetting savings in electrical and cooling loads. The benefits from daylighting are maximized when both occupancy and lighting sensors are used to control the electric lighting system, the U.S. Department of Energy cites in the Energy Renewable Energy Building Technologies Program.

This is where the electrical contractor comes in. While they typically don't have much to do with the variations in daylight availability, along with the window, glass and skylight specifications, contractors work with the electric lighting design that integrates with the daylighting layout. This is critical for the success of the system.
Currently there are three types of advanced lighting controls available in the marketplace — switching, stepping and dimming controls.

Switching Controls. On/off controls simply turn the electric lights off when there is ample daylight.

Stepping controls. Provide intermediate levels of electric lighting by controlling individual lamps within a luminaire.

Dimming controls. Continuously adjust electric lighting by modulating the power input to lamps to complement the illumination level provided by daylight.