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Written evidence from HTA Design LLP


This response to the Environmental Audit Committee’s call for evidence on the best routes to net zero for future building needs comes from HTA Design LLP. 


HTA Design LLP is a leading practice of designers and placemakers in the built environment, specialising in development and renovation of homes and neighbourhoods of all kinds. We offer professional services over a full range of disciplines including; Planning, Urban Design, Community Engagement, Landscape Architecture, Environmental & Sustainability Consultancy, Architecture (pre & post planning), Community Engagement, Communication Design, Wayfinding, Web Design & Maintenance.  The full range of services we offer is available to view on our website We have studios in London, Edinburgh, Manchester and Bristol accommodating a team of 250 colleagues.


As housing specialists our response focuses on the housing sector and is set out under the following headings:

  1. Whole Life Carbon Regulation
  2. Embodied CO2 emissions in construction
  3. Operational CO2 Emissions
  4. Fiscal Incentives
  5. Home Performance Labelling
  6. Post occupancy Evaluation


  1. Whole-life Carbon Regulation


The UK Green Buildings Council published a report in 2020 titled ‘Net Zero Carbon Buildings’ which sets out a strategy for achieving net zero carbon buildings in the construction industry. As participants in the writing of the report we believe that it is a valid approach and one which should be further developed and taken into policy by the UK Government.


The UKGBC report highlights the need for buildings to be zero carbon over their whole life. This includes consideration of the emissions relating to construction, operation and demolition.


The principle ‘the polluter pays’ is important and should be applied to this sector as it is applied elsewhere. Applying this principle, the logical outcome is that the developer/contractor who manages the design and construction process is responsible for handing over a ‘zero carbon’ construction project, and a ‘zero-carbon-ready’ building for the end-user to operate it. The end-user is then responsible for the building emissions during the building’s lifetime on an annual basis and is also then responsible for the emissions at demolition.


Currently there is no mechanism by which home users are penalised for the carbon emissions of their homes in the same way that they have been penalised for high emission vehicles through road taxation and parking charges, as well as the congestion charge in London, all of which have helped to raise the profile of lower emission vehicles and stimulated the market for them.  No similar policy exists in the housing market.


  1. Embodied CO2 emissions in construction


Currently many local authorities impose a carbon tax on development which calculates an amount of predicted emissions over the 30 years after the building is completed, and assigns a sum of money to each tonne of emissions, payable by the developer to the planning authority and intended to be used to upgrade existing stock to reduce their emissions.  These emission calculations cover the energy use of the finished building, which the contractor/developer is not responsible for, and ignores the emissions used to construct the building in the first place, which the developer/contractor is responsible for.


The only authority dealing with embodied energy that goes into the construction of the building is the GLA, which now requires all referred schemes to submit a pro forma spreadsheet detailing the emissions produced in construction. This is not linked to any payment of an offset or linked to any standards but is aimed at tracking the emissions resulting from construction and represents a useful step forward in developing the knowledge needed to assess and then regulate these emissions. In order to reduce those emissions, we need to penalise buildings that exceed benchmarks, and then over successive decades lower the benchmarks. The RIBA 2030 Climate Challenge (  provides a useful set of benchmarks for this purpose, but these need to be tested comprehensively against practical examples.


Recent changes to Building Regulations regarding fire safety have created a serious set-back to these efforts. Wood is classified as a combustible material and has been banned from use in the external walls of most buildings. Even where it is not banned, insurers and asset managers are viewing it as an increased risk and either refusing to take over buildings with wooden construction or are increasing the insurance premiums. Given that timber construction has been around for thousands of years and is the single best material from a climate perspective, as it absorbs and locks up carbon in construction for the lifetime of the building, this could not have happened at a worse time. This aspect of the Building regulations deserves urgent review.


  1. Operational CO2 emissions.


Current regulations in the UK only deal with operation of the building, and not with all of the operational energy used in buildings. Part L Regulations deal with the ‘regulated’ energy used in domestic buildings, such as heating, lighting, and domestic hot water, ignoring domestic energy use for cooking, entertainment, home working or car charging. As we tighten the domestic regulations and reduce the need for heating energy, and as domestic car charging rises, the proportion of regulated energy use in new dwellings reduces and the proportion of domestic energy for other uses will rise. For us to truly deal with operational energy emissions we need to be setting targets for all energy use by occupants, and monitoring this on a household basis, or expanding Building Regulations to cover all energy use in the dwelling.


  1. Fiscal incentives.


A report published in July 2013, “Retrofit Incentives” ( from the UK Green Building Council has highlighted how fiscal measures can be used to incentivise renovation, demonstrating what Government needs to do to in terms of changing policy and introducing fiscal incentives that will help consumers make better informed decisions to drive this transformation. The measures suggested in the report included using Stamp Duty Land Tax or variable rates of Council Tax. These are designed to reward the purchaser of more sustainable homes. The same measures will work to improve the quality of new buildings as they would also benefit from lower taxation at the point of sale, or during occupation. This will be seen as an additional benefit of new homes to buyers, particularly those who prefer to buy existing homes rather than newly built ones. By comparing the energy efficiency of existing homes with new ones a strong signal will be sent to the market that newbuild homes have much to offer in terms of lower utility bills.


The British Government is moving to create a framework of regulation for mortgage lenders designed to incentivise regulation.  Following a 2017 Call for Evidence on ‘Building a Market for Energy Efficiency’, a 2020 consultation was launched to establish how best to improve the energy performance of domestic properties through obligations on mortgage lenders.  The consultation recognises that the stock of homes in the UK is older on average than the rest of Europe and proposes energy performance improvements to help with reduction in Carbon emissions, reducing energy demand so as to prepare the way for low carbon energy sources, increase the quality and value of homes, support the creation of high quality jobs in renovation and improve the nation’s energy security.


There is already a European initiative to introduce Energy Efficient Mortgage (EEM) to the market. These aim at incentivising borrowers to acquire highly energy efficient properties or to invest through renovation in energy efficiency. Incentives would include favourable mortgage financing conditions and relaxed limitations on loans offered to finance the energy efficiency improvement of homes related to upgraded (EPC) level.


  1. Home Performance Labelling.


To enable effective regulation of energy use, whole life carbon and provide a lever for fiscal incentives, we believe that the carbon footprint of homes should be much more clearly identified in the market place than at present with embodied carbon and energy consumption clearly advertised at point of sale alongside other empirical information, including the data sets covered by the RIBA 2030 Climate Challenge.


It is the role of regulation to set minimum performance requirements. But improved performance above this baseline can also be driven by the market. This can be achieved by providing better information to consumers that encourages higher performance through customer pull. This is best achieved through a systemised labelling of building performance developed by industry and facilitated by an independent standards authority so that it is applied universally by suppliers and agents.


A pilot research study into these Home Performance Labels was carried out by The Housing Forum in 2015 ( ).  This proposal was based on the EU Directive on the Energy Performance of Buildings which came into effect from 9 Jan 2013 with the introduction of Energy Performance Certificates. The pilot proposed that a statutory requirement to produce this information might form the foundation to include other information at the point of sale or rent on building performance with clear and simple metrics to ‘nudge’ consumers into making informed choices. The key performance measures chosen for the study on the basis that each is readily available and also considered most useful to consumers are those with a cost impact, such as:



The report proposed that providing this information in a standard format enables consumers to benchmark products against baseline requirements, best practice and other industry criteria. It also allows consumers to make market comparisons on the costs of purchasing or running the home, so driving housebuilders to deliver higher levels of performance in order to match consumer expectations and to achieve market differentiation. A smartphone App can enable consumers to calculate whole home, whole life costs when they purchase a house.


  1. Post Occupancy Evaluation.


The RIBA 2030 Climate Challenge requires practices to undertake post occupancy evaluation on all projects to test outcomes and to check on a number of other measures, ensuring that overheating was limited to 25-28°C, daylighting was sustained at 2% average daylight factor, humidity kept below 70%RH and internal CO2 levels below 10000ppm.  An updated RIBA Plan of Work for architects, revised manuals and guidance, and a refreshed Code of Conduct, placing a stronger obligation on meeting the public interest were published in the same year.  The RIBA set about collaborating with sister institutes to establish equivalent targets in related built environment professions and set up mechanisms for the collection and aggregation of data to measure the profession’s success (or otherwise) in achieving the targets. The issue for the professions, and hence for the planet, is that the long-term vision, the aspiration and the behaviours to achieve it are not consistently in place across the industry.


We have had some success but progress is slow and one issue is that developers and their insurers are often reluctant to undertake POE for fear of discovering what they would rather not know. Another problem is the lack of consistent benchmark parameters and criteria that would make aggregation and comparison of data effective. To overcome these obstacles, Government must mandate post occupancy evaluation initially on all projects involving public finance and incentivise the insurance industry to enable the feedback loop.  A central agency should be tasked with collecting, aggregating and sharing the data collected.


Benjamin Derbyshire l Chair

Rory Bergin l Partner, Sustainable Futures

HTA Design LLP


May 2021