Energy Performance Certification in New Builds: A Practical Guide for Construction Companies

The construction sector is facing a growing demand for more efficient and sustainable buildings. In this context, energy performance certification in new builds is not just a legal requirement, but a key tool for guaranteeing the quality and value of constructions. For any construction company, thoroughly understanding this process and its implications is fundamental, not only to comply with current regulations but also to differentiate themselves in an increasingly competitive market.

This certificate, mandatory for all new constructions for years, evaluates the energy efficiency of a property, assigning it a rating from A (most efficient) to G (least efficient). It is not a simple final procedure, but a process that begins in the design phase and extends throughout the entire execution of the work.

What is Energy Performance Certification in New Builds and its Regulatory Framework?

The energy performance certification of a building is an official document that verifies the amount of energy a property consumes and the carbon dioxide emissions it generates under normal conditions of use. It is an indicator of the building's energy performance. For new builds, this certificate is issued based on the project and, subsequently, ratified or modified once the work is completed, before obtaining the first occupation licence or habitability certificate.

For instance, in Spain, the primary regulatory framework governing this procedure is Royal Decree 390/2021, of 1 June. This decree establishes the calculation methodology and the basic procedure for certification. In turn, it is supported by the Technical Building Code (CTE), especially the Basic Document for Energy Saving (DB HE), which sets the minimum efficiency requirements that buildings must meet. These regulations originate from European directives, such as the Energy Performance of Buildings Directive (EPBD), which aim to reduce energy consumption and emissions in the European Union's building stock.

The importance of this certificate lies not only in its mandatory nature. A building with a high energy rating (A or B) not only consumes less energy, which translates into significant savings for the end-user, but also offers greater thermal and acoustic comfort, and contributes to environmental sustainability.

The Role of the Construction Company in the Certification Process

The construction company plays a decisive role in achieving a good energy rating. While the initial design and calculations are the responsibility of the designers (architects and engineers), the construction company is responsible for executing the work according to those parameters and ensuring that the materials and systems installed comply with the specifications.

Design and Project Phase

Although not a direct phase for the construction company, good communication and early collaboration with the design team are essential. At this stage, the elements that most influence energy efficiency are defined:

• Thermal Envelope: Choice of insulation, type of enclosures, thermal bridges.
• Joinery and Glazing: Selection of high-performance windows, with thermal break frames and low-emissivity glazing.
• HVAC and Domestic Hot Water Systems: Installation of efficient equipment (air-source heat pumps, geothermal, condensing boilers) and renewable energy systems.
• Ventilation: Mechanical ventilation systems with heat recovery.

The construction company, with its execution experience and knowledge of material costs, can provide valuable information to optimise the solutions proposed by the designers, seeking a balance between energy efficiency and economic viability.

Construction Execution Phase

This is where the construction company demonstrates its ability to transform the design into reality, ensuring that efficiency standards are maintained.

• Quality Control: Constant supervision to ensure that the installed materials are those specified in the project and that their placement is correct. For example, poor installation of insulation or joinery can generate thermal bridges or air infiltrations, reducing the final rating.
• Airtightness: Special attention to the continuity of insulation layers and the correct joining between different constructive elements to prevent air leaks. Air permeability tests (Blower Door test) are often carried out to verify this aspect.
• Installations: Ensure that HVAC, ventilation, and domestic hot water production equipment are installed according to the manufacturer's and project's technical specifications, and that appropriate commissioning is carried out.
• Document Management: Collect and organise all relevant documentation: material data sheets (insulation, glazing, joinery), equipment conformity certificates, installation reports, "as-built" drawings. This information will be crucial for the certifying technician.

Any deviation from the original project that affects energy efficiency must be communicated and, if necessary, justified and approved by the certifying technician.

Completion and Handover Phase

Once the work is completed, the construction company must provide the certifying technician with all the documentation collected during execution. The technician will conduct a final visit to verify the correct execution of key elements. With this information, they will issue the definitive energy performance certificate.

The construction company, in collaboration with the developer, is responsible for registering this certificate with the competent authority of the corresponding autonomous community (or local/regional body in other countries). Without this registration, the first occupation licence cannot be obtained, an indispensable step for the handover of the building.

Key Technical and Regulatory Requirements to Consider

To achieve a good energy rating, construction companies must pay special attention to several technical aspects defined by the CTE DB HE (or similar national building codes):

1. Thermal Insulation of the Envelope: The quality and thickness of insulation in facades, roofs, and floors are critical to reducing heat losses and gains. Low thermal transmittance is sought in all enclosures.
2. Exterior Joinery: Windows and doors must have good thermal insulation (frame with thermal break) and high-performance glazing (double or triple glazing with air or noble gas cavities, and low-emissivity coatings).
3. Solar Protection: Elements such as overhangs, louvres, or blinds are important for controlling solar radiation in summer and preventing overheating.
4. HVAC and Domestic Hot Water Systems: The installation of high-energy efficiency equipment (heat pumps, condensing boilers) is required, and in many cases, the contribution of renewable energies for domestic hot water production (solar thermal, air-source heat pumps).
5. Ventilation: Ventilation systems must ensure good indoor air quality with minimum energy consumption. Heat recovery units are a common solution to reduce energy losses associated with ventilation.
6. Lighting: Use of efficient luminaires (LED) and control systems (presence or daylight sensors) to optimise electricity consumption for lighting.
7. Airtightness: Good sealing of the envelope reduces unwanted air infiltrations, which can account for up to 30% of energy losses in some buildings.
8. Thermal Bridges: Careful design and execution to minimise points where the envelope loses insulation continuity, such as corners, slab-to-facade junctions, or window perimeters.

Compliance with these requirements is not only an obligation but also an opportunity to build buildings of higher quality and market value.

Common Challenges for Construction Companies

Energy performance certification, despite its benefits, presents specific challenges for construction companies:

• Coordination: The need for early and constant integration with architects, services engineers, and the certifying technician themselves. A lack of communication can lead to costly errors on site.
• Document Management: The volume of technical information, material and equipment certificates, and quality control records is considerable. Keeping this documentation organised and accessible for audits or for the certifier is a challenge.
• Staff Training: Site personnel need to be familiar with specific construction techniques for energy efficiency, such as the correct sealing of membranes or the installation of insulation without discontinuities.
• Cost Control: High-efficiency materials and systems often have a higher initial cost. Rigorous budget control is necessary to integrate these costs without compromising project profitability.
• Timelines and Bureaucracy: The certification process adds an administrative layer that must be managed within the project schedule to avoid delays in handover and obtaining licences.
• Execution Errors: Small oversights on site, such as poorly installed insulation