Expedia.com®, the world’s leading online travel agency, announced today that a first wave of 300-plus properties using LightStay(TM) within the Hilton Worldwide portfolio of hotel brands will be added to the Expedia.com Green Hotel Program. LightStay is Hilton Worldwide’s proprietary sustainability measurement system, on par with many of the best-in-class systems globally. With the addition of these hotels, the Expedia.com Green Hotel program now includes more than 2,000 hotels, giving Expedia.com one of the most comprehensive selections of eco-friendly travel options among all online travel agencies.

“Expedia.com is committed to helping travelers find the broadest range of ‘green’ properties in the industry,” said Tim MacDonald, senior vice president and general manager, Expedia.com. “The inclusion of Hilton Worldwide’s brands, that use the LightStay system, in Expedia.com’s Green Hotel Program helps fulfill that commitment.”

LightStay is Hilton Worldwide’s proprietary system developed to calculate and analyze environmental impact of its properties. The system measures energy and water use and waste and carbon output at the company’s hotels around the globe. It specifically analyzes performance across 200 operational practices, such as housekeeping, paper product usage, food waste, chemical storage, air quality and transportation. By December 31, 2011, all of the more than 3,600 properties within Hilton Worldwide’s global portfolio of brands will use LightStay.

“We are proud to become members of Expedia.com’s Green Hotel Program. Operating our properties globally in a responsible and sustainable manner is a priority for our company and a central part of how we do business,” said Paul Brown, President, Global Brands & Commercial Services, Hilton Worldwide. “By integrating sustainability performance as a brand standard, evaluated on the same level as service, Hilton Worldwide has become the first major multi-brand company in the hospitality industry to require property-level measurement of sustainability.”

To confirm the effective implementation and validity of LightStay, Hilton Worldwide commissioned KEMA-Registered Quality, Inc., a management systems assessment and certification company, to perform a series of third-party audits of LightStay. The extensive audit revealed that LightStay is a best-in-class system for measuring and analyzing sustainability performance data at hotel properties.

The Expedia.com Green Hotel Program launched in April 2008 and now features more than 2,000 supply partners and more than 80 green certification programs. Travelers who are interested in the Expedia.com eco-friendly travel options can now book at any one of the thousands of green-certified properties listed on Expedia.com including the recently added properties within the Hilton Worldwide portfolio of hotel brands.