Contemporary homes are built with open floor plans, great rooms, and high ceilings — a result of current tastes, as well as programmatic and structural changes in residential architecture. Unlike homes from the mid-century and prior, the contemporary home incorporates the previously private kitchen into the public living space and capitalizes on longer span beams to create rooms that flow together.

Second-hand. Hand-me-down. Left-over. Whatever you call it, it still means used. And who wants that? Well, we here at Re-Nest hold a special place in our hearts for the pre-owned and refurbished, because we know that reuse means less waste of natural resources and money. And while some things are clearly better new, salvaged building materials and furniture can be luxurious in a way that off-the-shelf products rarely are — that is, hand crafted, laboriously detailed, and well made.

A few weeks ago, I wrote about Wattbot, a new online tool that does a custom calculation to determine which home improvements will give you the biggest bang for your buck in terms of energy savings. This week, Wattbot launched its public beta for users in San Francisco, San Diego, Los Angeles, and New York. If you live in one of these areas, go ahead and give it a try. (And even if you don’t, you can pretend you do while giving it a test run. I won’t tell!)

As I get older, math increasingly becomes a private affair. Once considered to be good at it, I can now be found hiding out in the bathroom, counting on my fingers, when it comes time to divvy up a restaurant bill. Or quietly tapping on my calculator under my desk just to make sure that 60 inches is still 5 feet. (You never know when these things might change.)

The Holidays are all about Home. Kitchens filled with family recipes and helping hands; dining rooms stuffed with musical chairs. For some of us, Home is in front of the fireplace, on our parents' saggy couches from the 80s, and we wouldn't dream of changing a thing. (Well, maybe those drafty windows...) For others, Home is always evolving — constantly changing to reflect who we are becoming as people and as a society.

Whether you choose to go green by timing your showers, buying an energy-efficient furnace, or learning to love bamboo, one thing is certain: Green is an adjustment for all of us. It requires not just a change in habits, technology, and materials, but also a change in the way we think and the way we do.