A study by the ICF Kaiser Consulting Group for the US EPA's Energy Star
Homes Program found that homebuyers are willing to pay substantially more
for energy-efficient homes.
Energy Star homes use at least 30% less energy than a Model Energy Code home while maintaining or improving indoor air quality and increasing comfort. EPA estimates that the cost to upgrade a new home to Energy Star levels ranges from $2,000 to $4,000, and reduces utility bills by $420 per year.
For every $1 saved in annual utility bills, $20 is added to a home's market value.
Therefore, a savings of $420 a year in utility bills translates into an additional $8,400 for the home when it's sold.
To read the report: http://www.icfkaiser.com/consulting/docs/econcomm/homeener.pdf
EPA Energy Star Homes: