When the papers are full of stories about global warming and rising energy prices, green building stands out as a great solution for politicians. That has opened the door to advocates who are stepping up their efforts to get cities and even states to legislate the practice among home builders. Commercial mandates are in place throughout the country for state- and city-funded projects, and residential mandates are starting to appear.
The National Association of Home Builders discourages efforts to dictate and legislate what constitutes acceptable green building practices because green building needs to remain voluntary. Building science in this area is relatively new, and it's very dynamic. Builders try a new technique or product, and then look at the results to decide if it's worth trying again, or whether another approach is better. This trial process is what makes green building get better every year, as new ideas become standard practice, as builders see the benefits and vendors and suppliers get in on the action to meet their customer's needs. Green mandates take this dynamic process and freezes it into place. There's no room for innovation, no room for flexibility, leaving builders without choices.
On the other hand, the NAHB Model Green Home Building Guidelines and the NAHB National Green Building Program components are builder-friendly. They provide builders with choices within a framework, and that's what makes them so successful. They detail building practices that are flexible, replicable, market driven and cost effective. NAHB policy supports green building rating systems that quantify sustainability and resource efficiency in new home construction, while remaining voluntary, flexible and market driven; and reflecting regional differences and local building preferences.