Decoding Energy Efficiency Lingo

Sustainability and Green Building

The terminology for energy-efficient homes can be very technical and confusing. Here are some simple definitions to help you understand popular terminology as it relates to your home.

Energy-Efficient Home

A home that uses less energy than a traditional home without compromising service to owners and occupants. Energy efficiency can be achieved through improved thermal envelopes, solar-oriented construction, low-e windows and efficient appliances.

Learn the efficiency of your home is now and ways to improve it with ENERGY STAR’s Home Energy Yardstick.

If you are purchasing a new home, there are many programs that measure energy efficiency including:

  • National Green Building Standard (NGBS)
  • Enterprise Green Communities
  • Green Globes
  • Living Building Challenge
  • LEED

See how these programs compare.

Net Zero-Energy Home

A home that produces as much energy as it uses. The energy produced by the home must meet the household’s needs. Rooftop solar panels are perhaps the most common way for homes to produce energy. This is often achieved through renewable energy such as solar panels. To achieve net-zero energy, the home should be designed using a holistic approach that strives for efficiency and reduces energy consumption without sacrificing service or comfort.

Net Zero-Energy-Ready Home

A home that is outfitted with the necessary structural and technological support to install energy-producing technologies in the future. Net zero energy-ready homes are appropriate for home owners who would like the option to install energy-producing technology in the future. It is also a Department of Energy program that partners with builders and offers those professionals who build to specific requirements around energy savings, comfort, health, and durability — Zero-Energy-Ready Home. Take a tour of Zero today.

Net Positive-Energy Home

A home that produces more energy than it needs. A home owner may receive credit from their utility company for excess energy returned to the grid. It is energy either produced by specific technologies and saved through energy-efficiency measures.

Home Energy Score (HES)

A score of 1-10 is given to a home based on its energy use, with 10 being the most efficient. As with a miles-per-gallon rating for a car, the HES is based on a standard assessment of energy-related assets to allow for easy comparisons across homes in the housing market. This is a Department of Energy program often used for existing homes. To learn more, visit

Home Energy Rating System (HERS) Index

A score of 0-100 is given to a home based on an energy audit and report, with 100 being the least energy-efficient. The scoring system compares your home to a home built to code in 2006, which is known as the reference home. The reference home would score a 100 on the HERS index, whereas a newer home or one built to a green standard might score a 60. This is a Residential Energy Services Network (RESNET) program often used for new homes. To learn more, visit