Building Energy Classification
When we talk about energy class, we generally refer to the energy consumption required for the building in question.
The amount of energy consumed by the building to achieve a comfortable level of comfort is expressed by the building’s energy performance index (EPI).
Regulatory Developments
The concepts of energy class and energy performance index, briefly introduced above and now part of our daily lives, are actually the result of thirty years of legislative measures. “Regulations for the reduction of energy consumption for thermal uses of buildings” is the 1976 law that paved the way for countless updates, changes, and improvements, which have led to the mandatory requirement of what is now known as the Energy Performance Certificate (EPC).
Without wishing to delve into the analysis of the dozen or so laws and decrees mentioned above, it should be noted that the most recent regulatory update refers to Directive 2010/31/EU, and the latest changes to the Energy Performance Certificate (APE) were introduced in 2015-2016. These regulations define the professional requirements, the requirements for certifiers, and the applicable energy classes.
Professional and Certifying Requirements
In Italy, the previous option of self-certifying energy efficiency in Class G has now been superseded; any certification must be issued by a professional who meets the professional requirements for issuing the certificate, who complies with the accreditation criteria of the bodies authorized to ensure professional qualifications, and who is free from conflicts of interest.
Professionals must therefore be registered with recognized professional associations or colleges qualified to design systems and buildings; they must therefore include architects, engineers, surveyors, technical and agricultural experts, whether freelancers or employees.
It is possible that graduates of other disciplines, or unlicensed architects and engineers, may carry out energy certifications, provided they have previously completed specific courses.
They must be impartial; therefore, in the case of new construction, they cannot be involved in the architectural design and construction of the building to be certified. It is also possible that Regions and Provinces may conduct further checks following the APE, consulting other competent authorities.
Energy Classification Table for Buildings
The regulatory framework for the energy performance of buildings was completed on October 1, 2015, with the entry into force of the decrees of the Ministry of Economic Development of June 26, 2015.
With the decree “Guidelines for the Energy Certification of Buildings,” the new APE becomes uniform throughout the country and includes more information regarding the quality of the certified building.
The energy classification of homes follows a precise table, which identifies 10 energy classes (the first 7), from A4, the best, to G, the worst.
The higher the performance of the building, the better its energy class. The latter is calculated, as defined in the decree “Performance Calculation Methods and Minimum Requirements,” using reference buildings: a reference case is selected, for example, a building in class A1, which has the same characteristics as the building to be certified. It is then ensured that they are equally geolocated, have the same geometric composition, and enjoy the same exposure.
A building requiring certification is superior to the case study when the former falls within classes A1 to A4; however, the performance of buildings decreases as they move away from class A, from class B to the worst, G.
The class defined by the APE, in addition to identifying the characteristics of the building in question, must also include, where necessary, improvement proposals, which differ depending on energy retrofitting or major renovations. It must also include information regarding incentives or financial support for the proposed improvements. For the APE to be prepared, the certifier will need to conduct at least one inspection of the property in question.
The “Templates for the Technical Project Report” decree provides reference templates for the technical report, divided by type of work (new construction, major renovations, energy retrofits) and based on geolocation and province.
The UNI standards contain:
The climate data on which certifications are based, divided by province;
Climate limit data, broken down by province, for the correct sizing of heating and cooling systems;
Degree days, i.e., daily temperature differences and the climate severity index of the area;
Summer climate zoning for the entire Italian territory, also in this case to determine the heating and cooling needs of a building in a given location;
The method for calculating the radiant energy received by an oriented surface
In conclusion
This in-depth analysis aimed to illustrate, without excessive technicalities, a general framework related to the concept of energy class.
In summary. A home’s energy efficiency rating is the data, referring to an existing property, whether renovated or newly constructed, that provides the building’s energy consumption requirements and therefore defines its quality: the higher the rating, the closer it is to A, the lower the rating, the further it is from A.
The literal division into energy classes (building energy classification) is a simplification of years of legislation that has led to an increasingly detailed classification. Certification has increasingly become the responsibility of competent and impartial technicians, increasingly focused on reducing consumption, a benefit for both the environment and the owner (in the case of existing property) or buyer (in the case of new construction), who will see reduced consumption and costs over time.
In-depth analysis by the staff of Inside Project, an architecture and design firm in Verona and throughout Italy.