IN TODAY'S POST-HOUSING CRASH WORLD, a family's biggest purchase—a home—no longer necessarily equates to it being the best investment. Against the backdrop of this sad truth, the business of selling new homes has become increasingly more focused on the economics of homeownership than just the traditional emotional drivers pushing families toward it. Home builders have to deliver product with such value that it outweighs consumers' trepidation.

Value today starts and ends with price. For as penny-pinching as buyers are today, financing constraints also are necessitating that builders deliver homes real families can actually afford. But, as some builders are already finding out, builders who can layer on additional value by reducing not only the cost of the house but also the cost of running the house through energy efficiencies have a very powerful selling proposition—never a bad thing in a weak market.

But improving energy efficiency has historically resulted in additional cost, which in turn can jack up the price of a home at a time when less means more to potential buyers. However, a team of experts from the architectural firm KTGY, engineering firm Gouvis Engineering, and consultancy Continuum Advisory Group collaborated on a mission to retool a home to improve energy performance without adding hard costs.

The team was successful in its task. The seven major changes it made to the home design improved the energy performance of the house while saving more than $132 on the cost to build. And volume aside, the savings on a per-unit basis would only grow with larger, more complicated plans. Here's how they did it:

Click here for larger original plans image.

Click here for larger revised plans image.