Consider maximizing the natural light in your home or office by pulling up the window...

A rock warmed in the sun all day still radiates heat long after nightfall. That's the principle of thermal mass-the ability of a material to absorb and retain heat. In a structure, building materials with high thermal mass, such as concrete, brick, or tile, can absorb heat during the day and release it slowly back into the building at night, helping to keep interior temperatures constant. Even large tanks of water can serve as thermal mass. This is especially useful in climates with blistering days and chilly nights.

The two most important things to consider when shopping for "green" furniture are: What is the...