One of the basics- the biggest difference your house makes on the environment is by the energy it uses. We just got our first big rainstorm of the year here in N. Ca, and that got me thinking about wall systems. (Have I ever disclosed to the group that I am totally a green building nerd? I mean I am addicted, I am not even close to being in recovery, and I am ok with it.) We count on our walls to hold our buildings up, and never think about how many functions they provide to a dwelling. They are structural, yes, but they are also your first defense against the big bad world.First, water is the enemy of the wall, especially the wooden wall. A good contractor will think through the path that a drop of water would take down each piece of flashing and vapor barrier. Overhang, of course, will help keep the water off of the wall in the first place but a good builder will be as careful with every detail as if the wall had no overhang protecting it at all. Secondly, keeping a house cool or hot takes energy, why not help save energy and money by insulating? Insulate a lot, in fact. Insulate like a crazy person, exceed whatever standard is required. It will save you money, decrease the carbon footprint of your home, and you will be more comfortable. Insulation is very reasonable, compared to other energy saving upgrades. Detail makes a big difference with insulation, as it does with wall systems. A gap in the insulation around a pipe, blocking in the wall, or a power switch or outlet can decrease the R value of that entire section of wall. Fill the gaps, and put an insulation gasket behind your switch plate. Many local contractors can take a thermal picture of your wall from the outside to show you just how much heat you are losing through your walls. My friend Lorna is one that can help you out in the Bay Area. The picture shows a small house before and after insulation! What a difference! Walls are boring. When you spend money on insulation, or when your contractor takes the extra time to detail the flashing around the window the house does not look different or more beautiful. But think of it this way, Your walls should do more than just hold up the roof, they should be a cozy blanket around your house that keep you warm and dry. Make sure the details are right and they will be able to keep you comfortable. And did I mention you should insulate?