The U.S. Green Building Council has co-sponsored a report from the Joint Center for Housing Studies of Harvard University entitled The State of the Nation's Housing 2010, which studied the affordability, energy and location efficiency within the existing U.S. housing stock.
For the first time, the report also looked at the utility and transportation costs associated with current trends in the residential real estate market, finding that housing can be made more affordable through efficiency upgrades.
Utility and transportation costs greatly affect housing affordability for families at all income levels.
Released earlier this week, the report found the sale of existing homes in 2009 climbed five-percent, while new home sales were down by 23-percent.
Much of the growth in existing home sales is credited to declining real estate prices, along with government tax credits marketed to first-time homebuyers.
"As existing home sales begin to rise, the there is a great opportunity to bring the energy and water efficiency aspects of these homes up today's standards," said Casius Pealer, director of affordable housing policy, U.S. Green Building Council.
"The report found that if all pre-2000 homes were brought up to the same efficiency as post-2000 homes in their regions, residential energy consumption would fall by 22.5 percent - reducing the financial strain on American families and directly tackling our collective environmental challenges."