The U.S.-based EPA program rates the energy efficiency of appliances used in businesses. More than 241 hotels participate in the United States. A score of 75 out of a possible 100 is the minimum to be considered energy-efficient. You can search for certified hotels on energystar.gov.

The EU Eco-label is an official certification developed by the European Commission for its 25 member states for hotels, campsites, and consumer products. Its search able Web site, eco-label.com, offers an catalogue of eco-designated accommodations.

Based on stringent guidelines, Green Globe certifies properties in more than 80 countries. Its Web site, greenglobe.org, lists certified hotels by region and country.

The U.S. Green Building Council created this program to certify that buildings meet standards of energy efficiency, conservation, and community sensitivity. Go to usgbc.org.