In asking, 'What is interior design?' in today's environment, one must also begin to start thinking green and to look for ways to minimize the consumption of non-renewable energy sources. How does one create areas with a lot of natural lighting but not subject the individual to the blazing rays of the sun? How does one incorporate solar panels into the design or solar powered floor heaters in colder climates without losing the esthetic charm and ambiance of marble floors? These are the challenges of today's designers. It's a good thing that they love their jobs.