Growing up, when asked "what does your father do for a living?" I proudly answered, "He's Smokey the Bear's helper."
My dad worked for the U.S. Forest Service at a time when conservation wasn't the hot topic that it is today so it was right up my alley to become an Ecobroker. One of the concepts that was new to me, or at least, new in terms of language was "daylighting."
Obvious economic savings from house designs that use natural lighting include less use of electricity. Less apparent is how good you feel and how that might impact your productivity.
My recent issue of EcoBroker Update talks about studies that show how natural light is the "gold standard" by which the efficacy of artificial lighting technologies is gauged. It points out that people with access to windows and natural light are happier, more productive, and suffer fewer health problems than workers resigned to artificial lighting.
How does it work? Through skylights, efficient windows, light shafts, and architectural features that allow light inside. I loved the example that some Japanese shopping malls use fiber optic cables from the roof to bring in the light - Hmmmmmmmmmmmm - maybe that's the answer to the recession - more sunshine!
There are regional issues to consider with heat gain vs. heat loss. For more information, see http://www.daylighting.org/.