Innovative EPCs features in Italy: testing results and replication potential

30/08/2022

The focus of the Horizon 2020 project X-tendo is the further development of energy performance certificate (EPCs) schemes in EU Member States. After analysing the theoretical background, the project focused on testing its innovative features in concrete implementation projects. This series of blog post will help summarise the testing in each of the X-tendo 9 countries to understand the practical viability and the challenges in the implementation of the developed ideas and materials.

Depending on the feature, the X-tendo partners performed different types of tests: In-building tests apply the feature materials on concrete buildings, user tests consist of understanding the user perception related to the developed materials and ideas, system tests intend to understand the application of feature ideas and materials in related systems like EPC database systems.

Features and buildings tested in Italy

In Italy, the X-tendo’s partner ENEA tested three features to enhance current energy performance certificates: real energy consumption, district energy and EPC databases.

The first two features were tested as in-building test on 2 multifamily apartment buildings, whereas the EPC databases was done as a system test on approximately 2 million of EPCs in the Italian National EPC Database.

Summary of results from the testing

Real Energy Consumption

In Italy two residential building units in multifamily houses have been selected for the test, one with an individual heating system and one with a centralized heating system. These two different settings can be considered representative for two widespread heating system configurations for multifamily houses. For the two building units, the procedure usually adopted for EPC issuing has been carried out. In addition, the following energy consumption data has been collected: energy consumption for space heating per energy carrier and energy consumption for domestic hot water demand per energy carrier. The source for both types of data were energy bills from the buildings, but in case no dedicated energy bills for the specific energy service (space heating or domestic hot water) were available, the share of each energy service was assumed.

The challenges in implementing the test cases that were reported mainly concern the gathering of the necessary data: metering of energy consumption for different purposes within the buildings or apartments was not available. Consequently, the allocation of the energy consumption values found in the energy carrier bills to the different purposes had to be done based on information from users and assumptions / assessor experience. ENEA thus rated the overall feasibility of implementing the feature in the national EPC schemes as “somewhat unpractical”.

ENEA needed 150 minutes in total, but states that this might decrease to 90 in case that local weather data are centrally provided.

District Energy

The steps for the in-building tests of this feature were: 1. Administration / data collection – including gathering of building data, distribution of tasks and establish a testing strategy 2. Assessor evaluation – on-site visits, evaluation by the assessor and use of the provided calculation spreadsheets.

In Italy EPCs need to be issued for each building unit. This feature therefore has been on two residential building units / apartments in two different multifamily houses. The method adopted was based on the evaluation of the energy demand for both apartments and representative rooms, and on the collection of information and data on the heating elements present in the representative room of each apartment.

The overall implementation of the feature was perceived “somewhat easy” or “somewhat difficult”. The developed tool and guidelines were felt easy to use and the information on possible temperatures within heating installations in the building might show the possibility to change the heating source to a low-temperature source (even heat pump). However, to be practical for implementation into EPC schemes the spreadsheet tool must provide default data for all potentially installed radiator types. Assessors will not have the knowledge nor the time to adapt the tool to the local circumstances.

EPC Databases

In Italy, the National Italian EPC Database was tested on a “test environment” database containing nearly 2 million EPCs. The software code was used to perform two levels of checks: the first level controlling the presence and the correct data typology of 46 chosen parameters, and the second level, controlling that the values of 11 parameters are within a range defined by a certain percentile value, calculated by ENEA considering the EPCs present in the database. This level of checks aims to identify possible significant differences from the bulk of the EPCs stored in the database.

The major challenge in Italy was the high execution time of the code, that would allow to run it on the whole database only a few times in a year. A possible suggestion is to use a programming language “faster” than Python or the implementation of the threshold and percentile values calculation in the code.

Special attention must be paid to the definition of the rules. When defining first level rules, it is very important to avoid interdependencies with involved “critical” parameters. Through post-processing of the output provided by the code, it is possible to identify the faulty EPCs, the riskiest building clusters, and the parameters presenting the highest number of non-compliant EPCs.

Replication potential and conclusions

The implementation of Real energy consumption in Italy was challenging, mainly due to the difficulties in the data gathering and allocation. Metering of energy consumption for different use purposes was not available and had to be estimated based on energy bills, which was perceived complex, time consuming and uncertain. As meters for consumption of space heating and hot water preparation are very likely not present in most buildings, it is seen very relevant for the implementation of the feature to have a simple method for allocation of consumption values from energy bills. Additionally, for the implementation of the feature it is relevant to provide data on HDD, CDD and radiation for all locations in a country by an official body, so that assessors do not need to search for them on their own but can refer to standardised official values.

As for district energy, the EPBD recast proposal foresees the inclusion of information on the feasibility of adapting the heating system to operate at more efficient temperature settings in EPCs, while it also mandates MS to take necessary measures to supply buildings with district heating or cooling. The information from this feature regarding the DH types of fuels, CO₂ emissions and extension can be useful for other policies and planning besides the EPC, such as the DBL and the building renovation passport.

From a planning perspective, knowing the supply temperature of the DH can help authorities lower it in a district, in parallel planning the renovation of the buildings. Many EU Member States have already included the DH parameters in the EPC calculation method; thus, many necessary inputs are already available.

However, district heating parameters (the first set) in Italy would not have a big impact because of unequal geographical distribution (district heating only in the North), thus a big part of the country is not interested in district heating. But the second set of parameters is interesting for Italy where for renovations it is mandatory to be able to connect to district heating. The EED foresees that the country should report on the strategy for district heating/cooling, thus part of the feature can be used to assess the progress on the district heating. It can also be used by the national strategy to assess how to modernise and renovate buildings to adapt to low-temperature district heating systems.

The proposed revision of EPBD 2021 also makes it mandatory for each Member State to set up a national database for the energy performance of buildings, to allow data to be gathered on the energy performance of the buildings and on the overall energy performance of the national building stock. To ensure coherence and consistency of information, Member States are required to make their databases interoperable and integrated with other administrative databases containing information on buildings, such as the national building register and digital building logbooks.

The X-tendo EPC database feature has developed robust quality check mechanisms that could support a systematic risk-based quality control of completed EPCs. The outcomes from the verifications can define the threshold values to be implemented on on-site checks for issuing EPCs and if integrated with a feedback loop to the energy auditors and EPC issues, can improve the EPC issuing practices. The Italian testing showed that the feature needs to be developed specifically for the DB of the implementing country, IT skills, to operate on a DB, and a deep knowledge of the EPC scheme are needed and that special attention must be paid to the definition of rules: it is indeed very important to avoid interdependencies with involved “critical” parameters.

For more information on testing and recommendations, read the full report Implementation guidelines and replicability potential of the innovative features for the next generation EPCs here.