Although skylights are by far the most popular method of daylighting, it is not the most effective. Clerestory windows, or high vertically-placed windows, allow for much more light to enter a building. Clerestory windows, when properly placed, have a longer period in which direct sunlight can illuminate a room as opposed to skylights which are more effective during midday.
Savings from daylighting can cut lighting energy use by up to 75 - 80 percent according to the US Department of Energy's Federal Energy Management Program. In terms of cost savings, the DOE reported that many commercial buildings can reduce total energy costs by up to one-third through the optimal use of daylighting.
The California Public Utilities Commission also reports the average savings of customers who have put daylighting into place.
- An average grocery store could save roughly $16,000 per year (or up to 32 cents per square foot).
- A school could save close to $7,500 per year (or up to 23 cents per square foot).
- An industrial building could see savings of up to 12 cents per square foot.
Metro DC based My Organic Market found these numbers attractive enough to install 40 Solatube skylights in its newest location in Columbia East. They expect the sunlight to not only save energy, but produce a higher quality working and shopping environment. Scott Nash, Founder and CEO, said, "There is no better light than light from the sun. it not only requires less energy from the grid, which saves on energy costs and prevents pollution, but it has been proven to improve morale among both employees and customers in retail businesses. It's free light in its most natural form."