Insights

The UK Net Zero Carbon Buildings Standard

The UK Net Zero Carbon Buildings Standard (the Standard) is set to redefine how we design, construct, retrofit and manage office buildings. As the first industry-led initiative providing clear benchmarks for net zero carbon performance, the standard will demand greater accountability and transparency across the property sector. But what does this mean for workplace design, fit-out, and leasing?

Closer carbon monitoring of Cat A and Cat B fit-outs

One of the most immediate potential shifts will be the heightened scrutiny of Cat A and Cat B fit-outs. Historically, embodied carbon in fit-outs has been largely overlooked, with the focus primarily on base build emissions. The Standard will change this by requiring full lifecycle carbon assessments that include both operational and embodied carbon, ensuring that fit-out strategies align with long-term decarbonisation goals more holistically.

The recent Overbury study on “Counting the Upfront Carbon in Cat B Fit-Out” underscores the importance of addressing fit-out carbon emissions, revealing that Cat B emissions can reach half the total carbon cost of a new build shell and core. This is particularly significant given the high turnover rate of office fit-outs due to increasingly more popular short lease cycles, making cumulative emissions a pressing concern. The market is likely to shift towards a model where developers offer either a full shell and core or a fully fitted offering, allowing tenants flexibility while reducing wasteful strip-outs and fit-outs – is this finally the end of the obsession with Cat A?

A shift in materials, building systems… and buildings!

Material selection will be a key area of change. The Standard will encourage the use of low-carbon, recycled, and bio-based materials for both basebuild and fit-out. Expect an increased emphasis on products with Environmental Product Declarations (EPDs), as well as materials with lower embodied carbon, such as mass timber, recycled metals, and low-carbon concrete alternatives – is the supply chain geared up for this?

Upfront carbon targets are challenging and will only get tougher. There is growing consensus that achieving net zero carbon under the standard will become increasingly difficult for new buildings, and that retrofit and reuse projects will be the primary means of meeting the targets.

Heating, ventilation, and air conditioning (HVAC) systems will also need to evolve. All-electric solutions, such as heat pumps, are already becoming the standard, with a need for even further emphasis on smart, demand-responsive systems that minimise energy use. The inefficiency of regularly replacing HVAC systems with each new tenant fit-out will come under greater scrutiny, prompting longer-term thinking around adaptability and reuse – perhaps a change to the way we structure leases and legal obligations for both landlord and tenant.

Refrigerants and market readiness

Refrigerants will also play a key role in meeting the standard. While we are seeing most projects are generally able to meet the R32 threshold, there are still gaps in the market. For example, we’ve seen certain ducted heat pumps required for acoustic reasons do not yet have viable R32 alternatives. The industry is expected to catch up as F-gas regulations tighten, but some projects may face short-term compliance challenges. Can the refrigerant market innovate quickly enough?

Greater stability in building services across fit-out cycles

Research led by Hoare Lea in collaboration with the UK Net Zero Carbon Building Standard office sector task group found that MEP equipment can contribute up to half of a Cat B fit-out’s embodied carbon. This has prompted the introduction of minimum and median thresholds for Cat B MEP emissions, with a minimum scope of 25 kgCO2e/m² and a median of 47 kgCO2e/m². These figures highlight the need to reduce unnecessary replacements of MEP systems, shifting towards modular, adaptable solutions. Arguably a big ask in a workplace sector that has so often had quite the divide between ‘landlord’ and ‘tenant’ – collaboration will be key and perhaps the use of AI and data analytics can help bring this to reality.

Synergy with NABERS

Unlike NABERS, which provides a clear split between landlord and tenant energy use, the Standard does not yet differentiate energy targets. This creates inconsistencies in how performance is evaluated for basebuild schemes coming to market, as there are no clear rules on tenant energy usage assumptions. However, the pilot phase feedback may lead to a similar approach to NABERS, restricting tenants’ operational carbon and ensuring a clearer framework for shared accountability.

More attention to measuring building energy use

The vast majority of workplace buildings that will exist in 2050 are already built, meaning that retrofitting existing workplaces will be crucial. The transition to net zero will also require a shift in operational energy management, with both landlords and tenants needing to collaborate closely to monitor and reduce energy consumption.

For new build and major refurbishments, the Energy Use Intensity (EUI) targets in the standard need to be validated after a year’s operation in order to claim that the building is meeting the standard. This will require building owners to have full access to both landlord and tenant energy data, and ensure that the building is managed efficiently, or the building will lose its ability to claim it is meeting the standard. It will no longer be acceptable for building owners to let tenants use how much energy they want, and lease agreements will need to include clauses that require data sharing and best endeavours to collaborate on good energy management, potentially with limits on energy use.

Our involvement in projects piloting the Standard

Hoare Lea is actively engaged in projects that are pioneering approaches to net zero in the workplace sector, with some participating in the Standard’s pilot phase. These projects are providing early insights into the practical challenges and opportunities associated with net zero workplaces – across both basebuild and fit-outs. Initial findings highlight the importance of taking a carbon-conscious, holistic, interdisciplinary approach alongside focusing on reusing existing materials in order to significantly lower emissions without compromising flexibility or design.

The future is outcome-based

The UK Net Zero Carbon Buildings Standard will be a catalyst for a fundamental leap forward in the workplace sector – a sector that has already seen a turbocharged rate of change post-pandemic – a sector that often moves quickly to implementing and adopting new standards.

From design, materials, and systems to leasing strategies and data, every aspect of office design and fit-out will come under closer scrutiny. Those who adapt early will gain a competitive advantage in a market that increasingly values sustainability, resilience, and long-term energy & carbon performance. We are committed to supporting this transition, helping clients navigate the complexities of achieving net zero in the built environment and ensuring that performance is achieved in implementation, not just design.

Outcomes matter.