Can I put on a green addition without redoing my entire house?

Absolutely! Also, going green doesn’t just apply to new construction. You can be green when you renovate even a single room (or an existing addition). You’re being green when you’re simply upgrading to a more energy-efficient water heater. You can also go green in stages—it doesn’t have to happen all at once. Think of green as a choice you can make every time you do a reno or need to make a repair or a purchase, even if it’s just a light bulb.

There are no set rules for how green you have to be unless you’re building a home that you want to be LEED certified as having met a set of criteria that defines a high-performance green building.

In general, green goals for an addition are the same as for any project: creating a space that’s more energy efficient, has less of an impact on the environment and is healthier for the people living in it.

To meet the needs of people looking to make green renovations, including additions, in 2008 the US Green Building Council (the org behind LEED certification) and the American Society of Interior Designers Foundation partnered to create REGREEN, the country’s first comprehensive educational program focused on sustainable residential remodeling. Their guidelines, which were developed by industry experts and went through a public comment period for feedback, cover all the elements of green building, including water and energy efficiency, materials and resources and indoor air quality, and can help guide any home reno, from an addition to a bath remodel to a green space. The guidelines, which you can download at http://www.regreenprogram.org/docs/regreen_guidelines.pdf, include great real-world examples. Their website also has a cool tool called the REGREEN Strategy Generator. You fill in the general parameters of your project using drop down menu tabs and get back a customized list of the green steps needed to implement your project.

Now back to that green addition. Start in the planning process and look not only at the addition itself, but also how it will impact your existing home. For instance, you might have a strong idea of where you want to build, but from a green perspective that addition might be better on a different side of your home, where there’s enough daytime sun to help heat it or where it will help shield the part of your main house that gets too hot at times.

Here are the factors that REGREEN suggests you take into account start with the design phase of your addition:

• Flexibility so that you can make future changes without new construction
• Self-contained heating and cooling, which avoids extending pipes and duct work from the main system
• No- or low-impact on the durability of your existing structure
• Using the appropriate foundation, passive solar strategies, a high-performance building envelope and advanced framing and roofing techniques for the most insulation possible

For home improvement professionals, REGREEN is also an educational resource; you can access presentations and educational offerings, complete coursework and get a certificate of completion.