Earlier this week, we ran a webinar bringing together specialists from across the built environment. With an extraordinary level of interest from practitioners, local authorities, and housing providers, the session reflected just how significant these changes will be for everyone working on London’s built environment.

Here, we summarise the key points covered, the evidence behind the proposals, and how you can respond to the consultation before it closes on Thursday 15th October at 5pm. 

A link to the public consultation can be found at the bottom of this page.

The current London Plan, adopted in 2021, established the net zero ambition through policies SI2 (minimum CO₂ reductions and whole life carbon calculations), SI3 (heat network connections) and SI4 (overheating management). The Draft London Plan 2026 replaces these with four new policies — GHR1 to GHR4 — representing a meaningful and deliberate step forward in how London regulates the environmental performance of its buildings.

Last summer, Hawkins\Brown collaborated with Etude, Levitt Bernstein, Currie & Brown, Hayne Tillett Steel and Publica to develop the evidence base that contributed directly to the proposed policies. The proposals are also consistent with Climate Change Committee advice, Environmental Audit Committee recommendations, the UK Net Zero Carbon Building Standard, LETI, UKGBC and RIBA guidance — a level of cross-industry alignment that would have been difficult to demonstrate in 2021.

GHR1: Energy Efficiency

Presented by Naomi Grint, Etude

The most fundamental change in GHR1 is the move away from percentage CO₂ reductions towards two new metrics:

• Space Heating Demand (SHD): Capped at 20 kWh/m²/year, with an aspirational target of 15 kWh/m²/year across all dwelling types
• Energy Use Intensity (EUI): Set by building type, for example 40 kWh/m²/year for residential

These metrics matter because they measure what actually happens in a building and, critically, what an occupier pays. Unlike percentage carbon savings calculated against a national building baseline, EUI is an absolute number that can be checked against real energy bills. It also removes reliance on fluctuating grid carbon factors.

Carbon offsetting has been removed entirely, meaning compliance must come from the building itself.

The targets were developed through a detailed review of existing evidence bases, bespoke modelling across multiple residential and non-residential typologies, and analysis of current regulations, industry standards, adopted local plans and monitored outcomes.

On cost: Currie & Brown’s analysis found that meeting GHR1 has modest cost impacts, ranging from a 1.7% saving for high-rise flats to a 2.7% uplift for low-rise flats, with offices slightly higher at 3.2%. When the removal of carbon offset payments is factored in, a mid-rise residential development could see an overall development cost saving of 0.4%, while delivering an estimated 20% reduction in annual energy bills for occupants.

GHR2: Low Carbon Heat

Presented by Thomas Lefevre, Etude

A heating revolution is underway, with the shift away from fossil fuels towards electrification reshuffling the options available for different building types and locations. GHR2 introduces a structured framework, the Low Carbon Heat Appraisal, to guide decision-making and provide the GLA and local authorities with transparency over the choices made by applicants.

The appraisal covers criteria across three areas:

1. Impact on residents and building users — including energy cost, long-term maintenance and replacement costs
2. Environment and performance — fossil fuel use, carbon content of heat and local air quality
3. Infrastructure and viability — the practicality of the chosen approach for the specific scheme

The policy also introduces a more location-based approach to heat network connections, with four distinct scenarios depending on proximity to existing or planned low carbon heat networks and whether a site falls within a heat network zone.

GHR3: Upfront and Whole Life Embodied Carbon

Presented by Louisa Bowles, Hawkins\Brown

GHR3 introduces minimum upfront embodied carbon targets into the London Plan for the first time, expressed in kgCO₂e/m² to ensure they are comparable and benchmarked against wider industry guidance.

The proposed baseline targets are:

• 500 kgCO₂e/m² for residential buildings under 11 metres
• 700 kgCO₂e/m² for residential buildings 11 metres and above
• 700 kgCO₂e/m² for Use Class E (commercial)

Aspirational targets are also included, recognising that the policy will be in place for a number of years and that material decarbonisation will continue to drive performance improvements over time.

For sites with existing buildings, GHR3 also requires a pre-redevelopment audit to assess whether structures should be retained, sitting alongside Policy GLE11 on the circular economy and reinforcing the principle that the embodied carbon already in a building has real value.

The targets were developed through extensive modelling by Hawkins\Brown and Levitt Bernstein, testing nearly 50 alternatives across different floor plate proportions, building heights, structural configurations and typical London ground conditions. Three levels of ambition were explored, with the chosen level 2 targets designed to drive lean design without pushing costs beyond viability.

On cost: Currie & Brown’s analysis found that, for the most part, there is negligible or no cost impact associated with the upfront carbon standards — either because lean design principles achieve the requirements without material specification changes, or because the baseline specification already meets them. Where an increase in cost was identified, notably for medium and high-rise residential, it was relatively small and largely attributable to a shift towards brick facade systems, which are already common across London.

GHR4: Heat Risk

Presented by Clare Murray, Levitt Bernstein

GHR4 is an evolution of the current overheating policy rather than an entirely new one but, as Clare Murray noted, after the summer we have just experienced, getting this right has never felt more urgent.

The policy applies to all major development and addresses two interconnected challenges:

• Urban heat island effect — strengthening requirements to ensure that the places we design do not contribute to rising urban temperatures
• Building comfort — prioritising passive design measures from the outset, so that buildings are inherently more resilient before mechanical cooling is considered

The policy connects closely with HN8 (housing design), where measures such as cross-ventilation, window operability and solar shading are maximised as part of the planning application, not retrofitted after permission has been granted.

A key finding from the evidence base was that under the current London Plan, passive measures were frequently being skipped, with mechanical ventilation systems being boosted rather than buildings being designed to reduce cooling demand in the first place. GHR4 aims to close that gap by making passive design a genuine first step, with architects, engineers and sustainability consultants working together from day one.

How to Respond to the Consultation

The consultation on the Draft London Plan 2026 closes at 5pm on Thursday 15 October. Responding is straightforward, but there are a few things to bear in mind:

• Create your login early — the portal can be slow, so don’t leave registration to the last minute
• Navigate to Survey Chapter 5 for the GHR policies covered in this webinar
• For each policy, you will be asked whether you find it sound
• Use the general comments box (Question 16) for any specific observations or requests for clarification
• If you have evidence to support your comments, upload it under Question 17 — evidence-backed responses carry significantly more weight

If you support these policies, it is important to say so. Demonstrating broad industry support is as valuable as any technical comment. If you have concerns, share them with evidence so that the GLA can understand and respond to them constructively.