The Basics of Energy Efficient Lights
Most daytime lighting choices are built into good house design: the inherent energy efficiency of using the sun's light (and heat) far outweigh any gains made by using low-cost bulbs or other powered options.
However, humans still need light after the sun has gone down so there are choices to be made for the proper selection and use of lighting fixtures and equipment. Studies show that about 20% of a home's electricity goes into lighting, so the savings should not be underestimated!