There's no argument we love the sun and it's many health benefits so why do we still build dark closed in spaces to live in? The benefits of natural light don't just stop at our health it extends to our financial well being. Lighting is often 15% to 20% of a homes electricity use and 30% to 40% of a business's electricity use.

Let the Sun in

For thousands of years we have evolved to live our lives in sync with the sun. We thrive during it's daylight hours and recharge during the night. It's only the past hundred years or so that we've tried to break the routine by creating synthetic light conditions that allow us to thrive a bit longer through the day but without the benefits of the natural sunlight. Studies have shown that natural sunlight has significant health and lifestyle benefits, some even indicate that natural sunlight has a dramatic positive effect on surgery patients, students, and even retail sales.

Daylight and the Circadian Cycle

The biological processes that regulate our sleepwake cycle make up our circadian system. Primarily through the use of the neurohormone melatonin, our circadian system regulates our patterns of alertness and sleepiness. Without exposure to normal 24-hour lightdark cycles, a persons sleepwake cycle can stray by as much as two hours per day.The cumulative effect of this can be significant. An imbalanced sleepwake cycle may produce advanced or delayed sleep-phase disorders and lead to chronic sleep debt. In The Benefits of Daylight Through Windows (2003), LRC investigators also noted that [p]eople with chronic sleep debt feel permanently tired and are unlikely to work effectively. Furthermore, in the 2006 longitudinal study Light at NightCancer Risks of Shift Work, researchers from Thomas Jefferson University (TJU), in Philadelphia, and the Mary Imogene Bassett Hospital, in Cooperstown, N.Y., found an increased rate of breast cancer in night-shift workers that resulted from the suppression of the pineal glands production of melatonin.With all these know benefits why would ever design a dark closed in space other than to save a few dollars on construction costs. Not having access to natural light dosn't nessearily mean doom for the occupants of that space unless you're afraid of what might lurk in the dark. there is an appropriate balance to the amount of natural light that is healthy for a balanced lifestyle and is critical to a healthy sleep-wake cycle.

Integrating Daylight with Design

For most of us our lifestyles are already centered around the movement of earth around the sun. Daylight is a predictable variable, only changed by solar position and sky conditions, rich in the short-wavelength portion of the visible spectrum found to support both alertness and circadian sleepwake cycles. As a result, daylight in buildings may support human health and well-being, particularly for people in northern latitudes who occupy areas near a window or other daylight sources. But regardless of latitude or exposure duration, daylight may support human alertness and productivity. At the same time, it is important to remember that it is the dailyand possibly the seasonalvariation associated with the daynight light and dark cycles that supports human health. Lighting manufacturers, for one, have jumped on the bandwagon and attempted to mimic these cycles through electric light sources and lighting systems.Designers can glean two points from this trove of research. First, daylit spaces hold the potential to yield substantial benefits, including increased energy savings, and improvements to human health and productivity.Many resources are available to guide decision-making in daylighting design, but three tasks that are critical to a successful daylighting installation are: the control of direct sunlight at visual living and working areas during all occupied hours; the provision of balanced natural light on interior surfaces, particularly between perimeter windows and key vertical surfaces within the interior volume; and the provision of sufficient ambient daylight illumination for visual tasks. Modeling and testing design decisions with the increasing selection of daylighting software tools play an important role in the design process.