28,000 homes, one benchmark: how Vesteda uses BREEAM to steer sustainability

How do you certify nearly 28,000 homes, spread across around 500 complexes? CFP Green Buildings supported Vesteda as BREEAM Expert in one of the largest BREEAM In-Use residential portfolios in the Netherlands. The recent recertification of this portfolio has been nominated for the internationale BREEAM Awards. Together with Longevity Partners as independent BREEAM Assessor, the entire portfolio was certified.

With BREEAM as an independent benchmark, Vesteda gains insight into the performance of the portfolio and the opportunities to further improve sustainability. “We don’t certify at the end to achieve the highest possible score,” says Stephan de Bie, Head of ESG at Vesteda. “We do it at the start, so it helps us improve sustainability.”

In search of a practical benchmark

Vesteda manages around 28,000 rental homes across nearly 500 complexes in the Netherlands. As early as 2018, the ambition was clear: to assess the sustainability performance of the portfolio independently and broadly, going beyond energy alone. Themes such as accessibility, materials use, biodiversity and climate risks also needed to become measurable.

Certification was meant to support this. Not as a marketing tool, but as an independent assessment and an international benchmark. Several certifications were considered, but according to Vesteda they did not offer enough transparency in how scores are calculated or how performance can be improved. International comparability was also lacking, while Vesteda’s investors operate globally.

The choice was made for BREEAM In-Use. For residential assets, this methodology had not yet been applied in the Netherlands, but it had already been launched by BRE in countries including the United Kingdom. Together with Longevity Partners, the Dutch Green Building Council and BRE, the methodology was made applicable to large-scale residential portfolios in the Netherlands.

In 2022, certification was carried out on an unprecedented scale. Nearly 28,000 homes and more than 600 certificates were issued within one year. Three years later, recertification followed. This proved to be far from a repeat exercise.

Recertification is not a simple repeat

The expectation was that the second round would be more efficient, as the foundation was already in place. In practice, this turned out differently. “BREEAM moved from version 6.0 to 6.1,” says Roger Toussaint. “That may seem like a small step, but it meant that much of the evidence was no longer valid or had to be rebuilt.”

This led to a fundamental choice. Reuse as much as possible to save time and cost, or invest in the updated version, which is more representative but requires more work. Vesteda chose the latter. “We started this process to get an accurate and futureproof view,” says Stephan de Bie. “Then you need to choose the method that best reflects that.”

For CFP Green Buildings, responsible for the expert role and the preparation of the assessments, this meant redesigning the approach. Which elements can be standardised across the portfolio, and what needs to be assessed per location? How do you ensure consistency at this scale?

According to Inge, the main challenge lies not only in collecting data, but in organising it. “At this scale, you need to decide in advance what you can standardise and where you need to go into more detail. Without that structure, you lose oversight.”

Longevity Partners fulfilled the assessor and audit role by verifying information, conducting site visits and submitting the final assessments to DGBC. “In a portfolio of this size, an interpretation of a BREEAM credit can directly affect hundreds of assessments,” says Roger Toussaint. “That is why consistency and efficient communication are essential.”

Where theory and practice differ

The parties point out the tension between what guidelines require on paper and what is feasible in practice, especially in residential buildings. Site visits are a good example. In commercial buildings, an audit is relatively straightforward. In residential buildings, this is different. “You are entering people’s homes,” says Toussaint. “You want to collect evidence, while respecting residents’ privacy.” Privacy therefore became an important consideration.

Technical differences also play a role. For example, BREEAM asks for glazing area, while EPC data records this including the window frame. It is essentially the same information, but differences in definitions make it difficult to align datasets. As a result, data that should be reusable often has to be entered again.

The scale of the portfolio also makes every change significant. If DGBC clarifies how a credit should be interpreted during the process, this can have a direct impact on dozens or even hundreds of complexes. According to Inge Westerink, this is an area where the methodology can still develop further. “In residential blocks with two or three dwelling types, you need to assess what is truly representative. How many homes do you actually need to visit to get a reliable picture? There is still room to better align the methodology with residential practice.”

“The main lesson? Start earlier. Align interpretations upfront and keep communication lines short.” “These are inefficiencies that do not affect the quality of the certificate,” says De Bie, “but they do cost time and cost.”

A sustainability passport, not a report

After the first certification round, Vesteda needed more than a year to properly analyse the data. Not because the data was missing, but because systems were not yet set up for portfolio-wide analysis.

The results are concrete. Climate risks are now mapped systematically and translated into policy. Water-saving measures are included as standard in maintenance and renovation. Condition assessments have been improved so they can serve as evidence. New developments are designed using BREEAM criteria in the brief, including the required documentation.

“You can say you have a sustainable installation,” says De Bie. “But you also need to prove it. That is at the core of a strong sustainability passport.”

Each complex now has a plan that integrates BREEAM categories. Investment decisions are linked to sustainability scores. Recertification takes place every three years, while monitoring continues via the ERP system.

A score of 29 per cent

Vesteda scores on average around 29 per cent. This may sound low, but BREEAM only rewards performance above regulatory requirements. Everything that is already required by law does not count.

“Every point you score is additional,” says De Bie. “But in the market, 29 per cent is sometimes seen as low, whereas it actually shows that you perform above the legal baseline.”

Value creation: who takes the first step?

For tenants, BREEAM currently plays a limited role. In the real estate market, however, this is changing. Valuers, lenders and investors are increasingly looking at sustainability risks and the long-term performance of real estate.

There is still no clear standard for how certification translates into value. “The exact value premium of certification is still difficult to quantify,” says Roger Toussaint. “But for large portfolios, it is becoming increasingly important to be able to compare performance in a systematic way. Certification helps to organise that insight at portfolio level.”

The question is who takes the first step. Should the sector move forward together, bringing investors, valuers and certification bodies around the table? Stephan de Bie takes a pragmatic view. APG, one of Vesteda’s investors, now simply requires certification for real estate investments. “If you wait until everyone agrees, you never start,” he says.

According to Inge Westerink, the strength lies in the strategic use of certification. “What Vesteda shows is how you can use certification to strengthen your strategy. Not as a checklist, but as a tool that helps you look deeper.”