The Hague, 22 May 2025 – As climate goals tighten, the real estate sector faces mounting challenges to cut emissions when renovating building stock. Deerns and its partners developed practical, scalable solutions to enhance strategies for Net Zero Carbon (NZC) renovations across Europe.
Renovations play a crucial role in the Net Zero Carbon (NZC) European ambition, as existing buildings make up most of the real estate stock. As property owners and investors increasingly focus on addressing Whole-Life Carbon considerations in their sustainability strategy, implementing successful Low Carbon renovations will be a complex yet critical challenge.
Recognising this, an ambitious initiative co-led by Deerns, Alliance HQE-France GBC and AIA Life Designers aims to enhance strategies for NZC renovations across Europe. The project spans France, Spain, Italy and the Netherlands, benchmarking insights against France’s existing progress to develop practical, scalable solutions while understanding the key levers that impact carbon results and carbon return time in different countries.
The Importance of NZC Renovations
Reducing emissions from both new and existing building stock is crucial in achieving climate goals. However, while tools, data and methodologies for Life Cycle Assessment and Low Carbon strategies in new buildings have gained traction, renovations remain underdeveloped. As Ana Cunha, Strategic Sustainability Advisor & CSR Director at Deerns, explains, “The market has ambition and traction when it comes to new buildings but, for renovations, knowledge and data are more limited, regulations are less strict and coping with existing site conditions is more complex. We need to bridge that gap with effective tools and strategies and with proper knowledge synergies.”
By focusing on Net Zero Carbon renovations’ potential, this initiative provides a framework for international investors and corporate stakeholders to understand and implement sustainable renovation practices, aligning with national and European wide decarbonisation efforts.
This project is part of the Building Life2 project, funded by the Laudes and Ikea Foundations and supported by the World Green Building Council (WGBC).
The project integrates an international dimension to follow an initial Net Zero Carbon Renovation research programme carried out in France in 2020 by the Alliance HQE-France GBC and AIA. At the time, five action levers were identified for reducing carbon emissions in existing buildings, highlighting the carbon payback time indicator based on 7 case studies representing the French market.
Rachel Chermain, CEO of Alliance HQE-France GBC, says, “It became clear that we need to expand this to a European scope to co-develop a common approach while taking into account regional specificities and needs. This will help to mobilise both private and public European stakeholders to act toward achieving a sustainable living environment for all.” Engaging with the Deerns teams in the targeted countries was key to this international analysis process.
The international NZC Renovation project focuses on four key objectives:
- Developing knowledge of data challenges, countries’ methodology maturity and carbon impact levers for NZC renovations in a European context.
- Building business cases to enhance understanding of carbon footprints across different countries, based on Life-Cycle Assessment and whole-life considerations.
- Supporting NZC renovation approaches with actionable strategies for emission reduction.
- Engaging stakeholders to promote awareness and practical implementation.
Addressing Key Challenges
One of the primary challenges in the field of NZC renovations is the inconsistency of available data, calculation tools and regulatory frameworks across European countries. This disparity underscores the need for a standardised approach that accommodates country-specific contexts while maintaining a uniform evaluation methodology and decarbonisation goal.
According to Ana, “A building’s carbon impact can appear lower in one country compared to another simply due to different scopes in calculations or energy mixes. Our goal is to make these discrepancies explicit and understood, ensuring comparability and consistency in carbon assessments. This supports the selection of best tailored solutions for Net Zero Carbon renovations.”
Lessons Learned
The initiative, whose report will be published in the first half of 2025, has already revealed several critical factors that influence the carbon performance of renovations:
1. The Role of Mechanical, Electrical and Plumbing (MEP) Systems and Materials selection
In renovations, MEP systems have a disproportionately high impact on NZC renovations compared to new buildings, where structural elements play a larger role. Optimising MEP design and reducing unnecessary loads can significantly cut carbon emissions.
2. Carbon Return Time (CRT)
This indicator measures how long it takes for carbon savings from energy efficiency improvements to offset the emissions generated by renovation materials and processes. Carbon Return Time varies significantly between countries, from as little as six years to over seventy, depending on local conditions and available technologies.
3. Energy Mix and Approach Boundaries
The study highlights how a country’s energy mix and product’s carbon conversion factor influence the final impact of a building renovation. Such understanding of geographical variations is important. The location of the asset impacts future Carbon Pricing and understanding how a similar building may result in a different Carbon Return Time.
4. National Readiness, Tools and Data
The project evaluated adoption maturity, the country-specific methodologies for Life Cycle Assessment (LCA), Whole Life Carbon (WLC) calculations and existing benchmarks.
Understanding regulatory landscapes and available data allows investors to make informed decisions when approaching renovations.
" An energy-efficient renovation is not always a low-carbon renovation, balancing embodied and operational carbon is crucial for real impact and for successful whole-life decarbonisation.
A Forward-Thinking Strategy
Beyond assessing existing conditions, the project aims to set a precedent for European Net Zero Carbon (NZC) renovation strategies. The goal is to provide property investors and real estate developers with clear insights into:
- The best methodologies for reducing renovation related carbon emissions, supporting the best combination of strategies.
- Market readiness for adopting whole life carbon assessments.
- How to navigate national regulations and leverage country specific incentives for sustainability, while understanding the variations in a portfolio’s carbon impacts given an asset’s location.
With the Energy Performance of Buildings Directive (EPBD) mandating lifecycle carbon measurement by 2028, the need for a harmonised approach has never been more urgent. The findings from this initiative will help shape the roadmap for policy frameworks and market adoption.
Deerns’ Role in Carbon Consultancy
For Deerns, this project serves as both an internal knowledge accelerator and an external industry contribution. Internally, it strengthens the firm’s expertise in whole life carbon design, further positioning Deerns as a leader in sustainable renovation consultancy across Europe. Externally, it fosters collaboration with key stakeholders, sharing insights and solutions that support international investors in their journey towards NZC renovations.
As Ana summarises, “This initiative isn’t just about research – it’s about action. By aligning technical expertise with market needs, we are paving the way for more sustainable renovations across Europe.”
“The renovation of existing buildings is a crucial issue if we are to achieve the Net Zero Carbon objectives by 2050 at a European scale,” emphasises Rachel Chermain. “With this research project, the Alliance HQE-France GBC is fulfilling its role as a catalyst for collective innovationand would like to thank its partners Deerns and AIA for combining their expertise to carry out this study of public interest.”
The NZC Renovation Programme is a game changer for the European property sector. With Deerns, Alliance HQE-France GBC, AIA and the support of Green Buildings Councils at the forefront, the initiative is set to drive meaningful change, supporting both policy makers and investors in achieving their sustainability goals across Europe.
