Energy Star is a joint program with the U.S. Environmental Protection Agency and the U.S. Department of Energy.  Their goal is to use energy sufficient products and practices to help save money and help use less energy thus lowering greenhouse  gas emissions.  Advantages for the consumer is they are helping reduce the rate of greenhouse gas emissions, use less energy, which in return helps save money in the long run with bills.

Some of the benefits that are included with Energy Star fixtures that are normally not included with non-Energy Star fixtures:

• Includes the bulb - GU24-base which is very common bulb/ballast combination. This will ensure that your ballast can always be replaced in future years. (Linear lamps also have similat requirements)
  
• Color rendition must be at least 80 - incandescent light bulbs have a CRI of 100, it has only been within the last couple of years that CFLs have reached a higher CRI measurement. In the past they were more in the 50-60s.
• Must have electronic Ballast - this means that your ballast will not hum and the bulb will light up without flickering.
• Fixture MUST have energy efficacy - this means that all ES lighting fixtures need to be energy efficient when measured against traditional fixtures.