A home energy rating is a measure of how energy efficient a home is, used primarily in developed countries. The energy rating can be used for both existing or new homes. If an existing home has an energy rating, it will be easier to implement improvements to increase its energy efficiency. Homeowners will be able to use the report to determine the most effective ways in which energy efficiency can be improved. A new home that has an energy rating allows buyers to compare the energy efficiency of homes they are considering purchasing.

In the European Union, the energy rating of homes, and buildings in general, is part of the Building Energy Certification.

A home with an energy rating can be used to measure its energy efficiency or estimate the efficiency of a home that is being built or improved. When a home has an energy rating before being built and occupied, it is called Project Rating. After being occupied and after a certain period, usually a year, an energy audit is carried out in order to know the real energy consumption. With this information you can Confirm the qualification and grant you the Definitive energy certificate.

From now on, energy evaluations or audits take into account the various climatic conditions of each city, region or country. Each country that implements these qualifications has specific national regulations for each part of the qualification process until obtaining the definitive energy Certificate.

On Saturday, April 13, 2013, Royal Decree 235/2013, of April 5, was published in the BOE[1]​, which approves the basic procedure for the certification of the energy efficiency of buildings, which requires all homes for sale or rent to have said energy rating certificate as of June 1, 2013. In addition, sanctions are established for those owners who fail to comply with this regulation. These sanctions refer to the sale or rental of a property without the corresponding certificate and are categorized depending on the severity of the offense: minor (with fines ranging between 300 and 600 euros), serious (with sanctions between 601 and 1,000 euros) and very serious (from 1,001 to 6,000 euros).[2]​.

The HERS index of the United States is a relative energy index that has a maximum of 100 when it corresponds to the "American Standard Building" standard and an index of 0 (zero) when the building does not consume energy from the grid. In this case it is known as a Zero Energy Building.