London’s commercial buildings face mounting pressure to meet EPC B and Part L targets. Discover how façade strategy is evolving to meet 2030’s energy and carbon challenges.
As the built environment faces rising pressure to meet evolving energy and carbon performance standards, the façade is emerging as a central focus for compliance, value retention and long-term asset performance. Developers, consultants and building owners in London are particularly affected by two regulatory drivers: the updated Part L of the Building Regulations and the Minimum Energy Efficiency Standards (MEES), which will require all commercial properties to achieve an EPC rating of B or above by 2030.
According to a 2023 report from the Greater London Authority (GLA), over 80% of London’s existing office stock currently fails to meet the EPC B threshold. This represents a significant portion of the market that will require substantial upgrades or risk obsolescence. For developers and property owners, the implications are serious: without proactive intervention, these assets may face reduced rental potential, higher vacancy rates and declining capital value.
The scale of the challenge is matched only by the opportunity it presents: to reposition buildings for the low-carbon economy of the future. With such a large proportion of London’s commercial real estate at risk of non-compliance, understanding how these regulatory frameworks impact façade strategy is not just important – it’s urgent. The ability to meet new standards will be a defining factor in future asset viability, influencing everything from planning feasibility to long-term leasing prospects.
In this first of two articles, we explore four key approaches shaping façade strategy in response to Part L and EPC B.
1. Façade Retrofitting as a Tool for EPC Uplift
MEES regulations currently prohibit the letting of commercial buildings with an EPC rating below E, but by April 2030, that minimum standard will rise to EPC B under proposals outlined by BEIS (now part of the Department for Energy Security and Net Zero). For many office buildings constructed between the 1960s and 1990s, this means urgent action is needed.
The building envelope is often the single greatest impediment to improving energy performance. Façades with poor insulation, air tightness, aluminium-framed single glazing or significant thermal bridging result in high levels of heat loss and energy inefficiency. According to UKGBC, the façade typically accounts for 15–25% of a building’s total heat loss, making it a critical area for EPC uplift.
Retrofitting – whether through over-cladding, window replacement or full recladding – is therefore one of the most direct and effective interventions. However, this approach must balance improved thermal performance with planning sensitivities, conservation area considerations, and commercial viability. A well-executed façade retrofit can increase energy efficiency while revitalising a building’s architectural identity, increasing tenant appeal and future-proofing the asset.
2. Meeting the Demands of Part L Compliance
Part L 2021 marked a major step forward in the UK’s drive toward net-zero, and it now imposes stricter limits on U-values, air permeability and thermal bridging. For example, the limiting U-value for wall elements in new non-domestic buildings is now 0.26 W/m²K, with even more ambitious performance targets often required to achieve compliance under the notional building specifications in Approved Document L, Volume 2.
Compliance is no longer achieved through prescriptive construction details alone. The new regulations demand photographic evidence and digital compliance reports at key stages of construction. For façade systems, this requires a greater degree of quality assurance and construction-stage transparency.
For refurbishment projects, especially where elements of the existing structure are retained, achieving compliant performance can be complex. Mixed material interfaces, junctions between old and new fabric, and internal layouts can all present detailing challenges. Early-stage dynamic thermal modelling, collaborative envelope design and airtightness strategies are now essential to successful delivery.
3. Embodied Carbon and Long-Term Resilience
While operational energy performance is the central focus of EPC ratings and Part L, embodied carbon is fast becoming a parallel concern. As highlighted in RICS’ Whole Life Carbon Assessment for the Built Environment, facades represent one of the most carbon-intensive components of a commercial building due to their materiality, structural complexity and maintenance demands.
London’s dense urban fabric adds additional pressure to reduce embodied emissions. Demolition and new-build projects face higher carbon penalties and planning barriers, while retained structures and adaptive reuse are encouraged under GLA’s Circular Economy Statements. As a result, high-performance retrofit façades – designed for longevity, adaptability and ease of maintenance – offer a viable route to both carbon savings and compliance.
Specifiers are now evaluating materials not just for their thermal performance, but for their Environmental Product Declarations (EPDs), disassembly potential and whole-life cost. Where possible, reusing or remanufacturing façade components supports both decarbonisation and sustainability targets.
4. Repositioning Legacy Assets Through Façade Transformation
Many of London’s 20th-century office buildings now face twin pressures: subpar energy ratings and outdated architectural appeal. In response, developers are increasingly pursuing deep refurbishment strategies that retain core structural elements while completely transforming building façades and MEP systems.
Such projects often aim to reposition the building as Grade A stock, suitable for modern tenant expectations and ESG investment criteria. According to BPF (British Property Federation) insights, buildings with poor EPC ratings are already attracting lower rents and valuations, and these trends are expected to intensify as 2030 approaches.
Façade transformation becomes a visible, high-impact signal of environmental and commercial rebranding. It allows for integration of new glazing, shading systems, natural ventilation strategies, and in some cases, building-integrated photovoltaics (BIPV). The result is not just compliance with regulatory drivers but enhanced performance, occupier satisfaction, and market appeal.
Closing Remarks
The pressure to align with EPC B and Part L is reshaping façade strategies across London’s commercial real estate. No longer just a weather barrier, the building envelope has become a frontline issue in sustainability, compliance and commercial relevance.
Façade design and delivery now sit at the intersection of performance, marketability and regulatory compliance. Success in this evolving environment will depend on early expert engagement, rigorous energy and carbon modelling, and an investment mindset oriented toward long-term resilience.
For developers and asset managers, the road to 2030 is narrowing. But for those who act now, addressing the façade offers a powerful opportunity not just to comply, but to lead.
External Sources
- Retrofit First Topic Paper – Submission Version, Westminster City Council, November 2024
- The Non-Domestic Private Rented Sector Minimum Energy Efficiency Standards, Department for Business, Energy & Industrial Strategy, March 2021
- Advancing Net Zero, UK Green Building Council (UKGBC)
- Approved Document L, Conservation of fuel and power, Volume 2: Buildings other than dwellings, 2021 edition incorporating 2023 amendments, gov.uk https://assets.publishing.service.gov.uk/media/63d8edbde90e0773d8af2c98/Approved_Document_L__Conservation_of_fuel_and_power__Volume_2_Buildings_other_than_dwellings__2021_edition_incorporating_2023_amendments.pdf
- Whole life carbon assessment (WLCA) for the built environment, RICS
- London Plan Guidance – Circular Economy Statements, GLA, March 2022
- BPF research on EPC ratings and commercial buildings in the UK, BPF, February 2025
https://bpf.org.uk/our-work/research-and-briefings/bpf-research-on-epc-ratings-and-commercial-buildings-in-the-uk/ (downloadable file)
