Energy certification is a procedure for quantifying the energy consumption of a building during its use. It indicates the degree of energy efficiency of a building, showing the CO2 emissions due to heating, cooling, domestic hot water, ventilation and lighting.
The European Directive 2002/91/EC requires the Member States to establish a certification procedure that makes available to prospective buyers or tenants information on the energy consumption of the target building. In Spain, the European directive is adopted by mean of the RD 47/2007. Since this Royal Decree was approved, the project documentation for new buildings must include a “Certificate of energy efficiency at design phase”, which must be validated by the architects at the completion of the works (“Certificate of energy efficiency of the finished building).
The technician in charge of calculating the energy rating for new buildings (also for modifications or rehabilitations, if certain assumptions are accomplished) may choose to apply a general option (CALENER) or a simplified method. In all cases, must be defined:
- The building envelope, its components, and its dimensions.
- The climate zone where the building is placed.
- The type of spaces and its volume.
- The characteristics of the following installations: heating, cooling, lighting, ventilation, DHW…
In 2013, a new Royal Decree (RD 235/2013) added the obligation of this certification to existing buildings too, so any building which is sold or hired in Spain has to have this information available.
The works to be carried out for the certification of an existing building show certain differences to the ones for a new building, due to degree of uncertainty, since you have to figure out some of the characteristics of the building to be analysed. They could be summarized in:
- Visiting the property:
- Observation and data collection:
- Construction system used, and elements in the thermal envelope.
- Equipments and installations.
- Dimensions of rooms and surfaces.
- Observation and data collection:
- Further data collection, interpretation and report elaboration:
- Getting information about the registration data of the property.
- Calculation of energy efficiency through the methods and software authorized by the Ministry of Industry.
- Drawing up the certificate gathering all data. It will contain, in addition to the rating, a document listing proposals to improve the score achieved.
The energy label classifies buildings on a seven letter scale, from the letter G (least efficient building) to the letter A (most efficient building).
The certificate will be added to the Registry of Certificates of Energy Performance that each region must have. The energy performance certificate and the related energy efficiency label are valid for a 10-year period. It is the responsibility of the owner to renew the certificate after this period. The seller or lessor of the property must show the energy label alongside the other features that promotes the building.