Net Zero Week: Retrofitting for a Sustainable Future
During Net Zero week, we had the opportunity to participate in a captivating discussion with prominent figures dedicated to sustainability at DB3. Matthew Savory, the chairperson of DB3’s Sustainability Working Group, Nassia Roditi, DB3’s Head of Net Zero, and Hasviter Monkley, a project architect currently working on a Passivhaus Enerphit retrofit.
Throughout the discussion, the panellists highlight the urgent need for widespread adoption of retrofitting practices. They emphasise that retrofitting is not merely an option but an imperative to address climate change.
What is the significance of retrofitting and why has it gained prominence in recent years?
What is the significance of retrofitting and why has it gained prominence in recent years?
Matthew Savory, Chairperson of DB3’s Sustainability Working Group
“Retrofitting, in the context of construction, refers to the process of replacing a component or system within an existing building. This can involve various improvements such as replacing the heating system or windows, as well as adding roof and wall insulation. In recent years, retrofitting has gained significant attention in the construction industry due to two main factors: the government’s goal of achieving a net zero economy by 2050 and the poor energy performance of existing buildings in the UK, which accounts for 34% of the country’s total CO² emissions.
A key point to consider is that approximately 80% of the UK’s building stock that will exist in 2050 is already in place. Unfortunately, these buildings have an average Energy Performance Certificate (EPC) rating of D, indicating poor insulation levels and inefficient energy usage. This emphasises the urgent need for retrofitting measures to improve the energy efficiency of existing buildings.
In addition to reducing operational energy consumption, retrofitting also has the potential to decrease the amount of embodied carbon compared to demolishing and re-building. This means that retrofitting can be a more environmentally friendly option when looking at the whole lifecycle carbon of a building.
One notable resource for guidance on retrofitting is LETI’s Climate Emergency Retrofit Guide 2021. This guide offers valuable information and recommendations to effectively address the challenges posed by retrofitting in the context of climate change and the urgent need for sustainable solutions.”
What is DB3’s approach to Retrofit?
What is DB3’s approach to Retrofit?
Matthew Savory, Chairperson of DB3’s Sustainability Working Group
“In order to achieve a net zero economy, we strongly believe that a significant programme of energy improvements to existing buildings is essential. This programme includes various measures such as improving insulation levels, replacing windows and doors, and implementing enhanced ventilation systems in buildings. To demonstrate our unwavering commitment to this belief, we actively participate in the RIBA’s 2030 Climate Challenge. This initiative encourages architects to gather feedback from clients regarding the energy performance of completed buildings. By compiling this invaluable data, a comprehensive database can be created that provides insights into the effectiveness of the UK’s journey towards achieving net zero emissions.
At DB3, we advocate for a fabric-first approach, which minimises the need for heating and cooling through improvements to the building fabric, rather than relying solely on more efficient building services and introduction of renewable energy sources. As proud supporters of the Architects Journal’s RetroFirst Campaign, we endorse the campaign’s objective of reducing the VAT rate on refurbishments from 20% to 5%.
When appointed to Retrofit projects, our first step is to assess the existing energy performance of the building. If the budget permits, we construct a digital twin that allows us to test various options. We then create alternative scenarios for energy improvements to provide our clients with a report recommending the most effective allocation of their resources. We recommend adopting an energy standard, such as the AECB Building standard or Passivhaus Enerphit.
To ensure the success of a retrofit project, it is crucial to plan the entire process in advance rather than addressing improvements incrementally. This approach guarantees that successive measures work in harmony and are implemented in a logical order. Furthermore, retrofitting should strive to maximise the performance of each element and aim for a net zero carbon compatible performance that is as close to that of a new-build as possible. If the budget does not allow for complete decarbonisation in a single phase, it is advisable to phase the process by element, such as introducing triple-glazed windows, rather than spreading resources thinly across all areas, which would only yield marginal improvements.”
Why does Embodied Carbon matter?
Why does Embodied Carbon matter?
Nassia Roditi, Head of Net Zero
“The embodied carbon associated with the construction of a typical new building can be equivalent to 20 years’ worth of its operational carbon emissions. As our new buildings tend towards ultra-low operational energy consumption, this could conceivably stretch to 40 years. Retrofitting existing buildings, whenever feasible, is expected to yield a more favourable climate change impact than constructing new ones over a span of 10-30 years (varying based on the specific net zero deadline).
When considering the benefits of retrofit it’s worth remembering that over 60 per cent of embodied carbon emissions are associated with the sub-structure, frame, upper floors and roof of a building. A deep refurbishment should retain these elements, meaning on average, the carbon footprint of a refurbished building is half that of the newly-built replacement.
Opting to extend the lifespan of a structurally sound existing building that can be adapted to accommodate future occupant requirements presents a lower carbon alternative compared to demolishing and constructing anew. By undertaking a retrofit project aimed at optimising the building’s energy efficiency and decarbonising its heat and power sources, it becomes possible to ensure that the structure remains capable of delivering both a comfortable environment and high energy performance for an extended period.“
Why is Passivhaus Enerphit useful for Retrofit projects?
Why is Passivhaus Enerphit useful for Retrofit projects?
Nassia Roditi, Head of Net Zero
“The Passivhaus standard, originally developed more than 30 years ago, has demonstrated it’s efficacy across numerous projects by achieving operational energy savings of over 90% compared to existing buildings. By employing a structured design process from the initial stages, Passivhaus minimises energy demand, and this achievement can be validated through a certification procedure, ensuring that the building performs as intended with no performance gap.
Recognising the challenges posed by existing buildings, the introduction of Passivhaus Enerphit in 2012 provides a solution. It relaxes certain standards in specific areas such as the airtightness target, acknowledging the inherent constraints of retrofitting, while still accomplishing substantial operational energy reductions exceeding 75% in many building types.”
Tell us about your experience using Passivhaus Enerphit at St Fagans National History Museum?
Tell us about your experience using Passivhaus Enerphit at St Fagans National History Museum?
Hasviter Monkley, Project Architect
“The main gallery and administration building at St Fagans National History Museum holds significant historical and architectural value as a Grade II listed structure. It was constructed in multiple phases from 1967 to 1972, making it one of Wales’ notable examples of modernist architecture. The museum itself is situated within a Grade I listed park and features reconstructed historic buildings, providing visitors with a comprehensive experience that delves into Welsh cultural traditions and the rich history of Wales.
In order to assess the most suitable improvements for the building, we conducted a benefit analysis considering the listed status and heritage impact assessment. Several options were evaluated based on their energy improvement potential and their impact on the building’s historical significance. Ultimately, a balanced judgement was made, taking into account various factors.
For instance, improving the thermal performance of the existing brick cavity walls is necessary to meet the required standards, but external wall insulation would have a greater impact on the building’s heritage compared to internal wall insulation. However, external wall insulation is more efficient in reducing thermal bridges caused by internal partitions. Detailed calculations and construction plans were prepared for both options, for discussion with conservation bodies.
In another example, the current single glazed timber windows, which hold heritage value, are in extremely poor condition. Therefore, it has been recommended to install new triple glazed composite windows.
An important aspect of the Passivhaus Enerphit standard is its recognition of constraints that may arise when working with existing buildings. The Enerphit standard can be achieved in one of two ways: the energy demand method or the building component method. Both methods have been tried out on this project to confirm which one is best suited for the project.
At present, the project is awaiting confirmation of funding before proceeding to the construction phase.”
DB3 Net Zero
DB3 Net Zero
DB3 Net Zero draws the experience of our in-house mechanical & electrical engineers, architects, energy assessors, Passivhaus designers and sustainability experts to achieve your net zero targets. Â
Medway Family & County Court
Medway Family & County Court
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