Sustainable Design

As architects, at InsideOut we see ourselves as champions of sustainability, and aim to play our part in the battle against man made climate change. But what do we mean by sustainability?

A lot of terms are used, sometimes interchangeably when discussing sustainability, and that is certainly the case in our industry. In part this article was written to help us clarify our own thoughts, as without a clear and deep understanding of all the issues we would not be able to explain them to our clients well enough to describe the benefits – and by benefits we obviously mean for the environment, but also in this context we mean benefits for our developer and housebuilder clients. It is fair to say that a sustainable scheme can cost more to build, but it is also the case that sustainability can add real value.

Sustainability is a broad term, and for this reason implementing a sustainable development strategy can be daunting. To demystify and clarify what sustainability is, it is useful to look at it from different perspectives, and at different scales, such as the Global (United Nations) National (UK Government policy) & Professional (RIBA)

Most people will probably have heard of the terms Sustainable Design, Zero Carbon, Net Zero carbon, Whole life carbon, Passivhaus or some other phrase, and whilst they get the gist, few people have a deep understanding of what these terms mean, so we will also run through these and review the benefits that these ideas can add.

What are the UN Sustainable Development Goals?

The UN has outlined Sustainable Development Goals, which are a universal call to action to protect the planet and improve the lives and prospects of everyone, everywhere.

This is certainly a powerful statement of intent, and the goals were adopted by all UN Member States in 2015, as part of the 2030 Agenda for Sustainable Development. The UN have set out a 15-year plan to achieve these goals.

The 17 goals sit into 5 overall categories, which are neatly encapsulated by five Ps – People, Planet, Prosperity, Peace and Partnership. They aim to create a better and more sustainable future for all, and address the global challenges we face, including poverty, inequality, climate change, environmental degradation and peace and justice.

Whilst all these goals are important, in the context of the construction industry, and the architectural profession, some of these goals can obviously be influenced more than others – Good Health & Wellbeing, Clean Water & Sanitation, Affordable Clean Energy, Economic Growth, Innovation & Infrastructure, Sustainable Cities & Communities, Responsible Consumption & Production, and Climate Action are all areas in which we can have a huge impact.

The UK government has aimed to embed these goals in policy throughout all government departments, and with particular reference to our industry the Ministry of Housing, Communities & Local Government published initial consultation on The Future Homes Standard in 2019.

What are the Future Homes & Buildings Standards?

The UK Government has set a series of sustainable development goals, and it aims to pursue a ‘net zero carbon’ economy. In 2019 the UK became the first major economy in the world to adopt a “Net Zero” emissions target into law. This legally binding target requires the UK to bring all greenhouse gas emissions to Net Zero by 2050

One of the governments key focus areas in this regard is construction, and as well as looking to influence how buildings are built, they are looking to push forward the delivery of low-carbon heating.

It has been calculated that new and existing homes account for approximately 15% of greenhouse gas emissions in the UK, and the wider built environment accounts for 40%, so by improving energy efficiency and moving to cleaner ways to heat our homes, we can significantly reduce carbon emissions and keep household energy costs low, now and in the future.

As a step towards achieving this target, the government have been consulting on a new “Future Homes Standard” which called for all new homes to be future-proofed with low-carbon heating systems and higher fabric efficiency. These standards are set to replace the now scrapped Zero Carbon Homes Standard, and Code for Sustainable Homes.

This “Future Homes Standard” has now been renamed “The Future Homes & Buildings Standards”, by the also newly renamed department for Levelling Up, Housing & Communities. And we wonder why people find some of the terminology in our industry confusing?

In addition to the proposed Future Homes & Building standards in 2025, major Building Regulations changes to Part L (fuel and power) and Part F (ventilation) will be coming into force in June 2022, as well as a new approved document Part O (overheating in new homes). These current year changes will already lead to a reduction of 30% of carbon emissions for new homes, as a step towards the new 2025 standards. The Future Homes and Buildings Standards will complement the Building Regulations to ensure that new homes built from 2025 will produce 75-80% less carbon than under current regulations.

Under the 2025 standards, new homes will need to adopt a Fabric First approach and adopt the Fabric Energy Efficiency standard to measure energy efficiency.

An important aspect of the 2025 Future Homes Standard is that reducing the demand for heating (and cooling) through improved fabric efficiency will not meet all the energy requirements. Fabric efficiency will need to be coupled with low-carbon heating systems such as air-to-water / air-to-air heat pumps, heat networks (district heating), and in some instances direct electric heating, as well as the use of other systems such as wastewater heat recovery. As the UK moves towards a decarbonised electricity grid (through increasing low-carbon power generation), homes utilising these systems will be able to heat themselves at net zero carbon. Gas boilers will become more and more obsolete and will eventually need to be replaced.

In addition to an uplift in efficiency requirements, it is likely that compliance and performance evaluation will be incorporated into the standards to ensure that proposed changes are actually delivered. For example, developers may be required to test all individual new dwellings for air tightness, as opposed to the current regime of sample testing.

There will need to be a continuation on the improvements already being seen in build quality to further reduce the gap between design intent and actual built energy performance. This will need to focus on continuity of insulation, thermal bridging at junctions and airtightness. Developers can ensure this improved build quality through more traditional forms of procurement, with a third party (i.e., Architect) responsible for site inspections, ensuring that the contractor is following the terms of the contract and having mechanisms to ensure compliance. But we would say that, wouldn’t we?

Clearly there are details to be addressed to ensure that the home building industry and supply chains are ready for implementation of the Future Homes and Buildings Standard in 2025. As well as challenges there are areas of opportunity, such as a new mass market solution for low-carbon heating. Current heat pump sales in the UK are approximately 20,000 units a year, compared to over 1,000,000 for gas boilers. The industry will need to transform to provide the skills required, and end-users will need to adapt to the new technology – Home User Guides will likely be specified as part of the new standards to educate owners on how to operate their beautiful new low-carbon homes.

What is the architectural profession’s approach to sustainability?

With regards to the architectural profession, the RIBA have committed to demonstrating leadership in delivering the UN Sustainable Development Goals. They have set the “2030 climate challenge” – Version 2 of which was issued in 2021, which focuses on the three environmental sustainability outcomes that all new or refurbished buildings contribute to: energy use, embodied carbon and water use with an overall aim to target net zero whole life carbon emissions by 2030.

This challenge sets measurable goals, and aims to reduce operational energy demand by 60% from 2021 figures, reduce embodied carbon by 40% against 2021 baseline figures (before offsetting), reduce potable water use by 40% and achieve core health and wellbeing targets, such as a reduction in overheating, increased daylighting and an improvement in air quality, as well as closing the performance gap to deliver agreed sustainability performance

The RIBA have produced a guide for architects – The RIBA Sustainable Outcomes Guide, which aims to distil the complexity of sustainable architectural design into a set of measurable and manageable outcomes that architectural practices can use daily on projects of all scales. Inside Out are committed to the RIBA challenge and use the core sustainable outcomes through all stages of design and delivery, via the RIBA plan of work. We see our responsibilities as twofold – looking to achieve these sustainable outcomes on all our projects and running our own business with a view to the implementation of the wider UN sustainable goals.

What is Sustainable design?

In basic terms, a sustainable design is one that responds to the Environmental, Social & Economic factors that affect both our environment and climate. It uses design strategies that reduce the negative impact of the built environment on the environment as a whole.

The construction, operation and then demolition of buildings is one of the most significant sources of carbon emissions, and a sustainable design and development strategy aims to reduce and where that is not possible offset these omissions.

There are a lot of different terms used to describe methods of reducing carbon emissions from buildings, and the buildings that result, such as.

A Net Zero Building

A building that has no net carbon emissions during its construction and operation. Where possible, emissions are reduced, and where not possible these are offset.

A Net Zero in Operation Buildings

A building where carbon emissions associated with its operational energy on an annual basis are zero or negative.

Net Zero in Construction Buildings

A building where carbon emissions associated with its construction are zero or negative.

Whole Life Net Zero

A building where carbon emissions that result from the construction and the use of a building over its entire life, including its demolition and disposal are zero or negative.


The gold standard of sustainable buildings. A building created with rigorous, quality assured and performance-based energy efficient design standards. They will maintain an almost constant internal temperature without need for heating or cooling. This standard creates very low energy buildings that use 75% less energy than an average UK new build. The buildings are highly insulated, highly airtight, and with particular attention to detail paid to minimising thermal bridging. Passive solar gain and mechanical ventilation with heat recovery are used are used to create a comfortable internal environment. The methodology behind a Passivhaus building differs from that of a Net Zero buildings, which use a combination of energy efficiency and clean energy generation to offset any energy use, whereas a Passivhaus aims not to use as much energy in the first place by being effectively sealed against the elements.

Whilst reducing carbon emissions is rightly a priority when discussing sustainability, there are many other equally important considerations, such as sustainable water consumption and disposal, biodiversity, urban greening, and sustainable transport. More focus also needs to be given to creating buildings that promote good health and wellbeing, and are inclusive, accessible and adaptable.

How do we achieve sustainable water consumption?

The water cycle is one of the most critical issues to be addressed in some regions of the world today. Whilst we are currently lucky in the UK that other than the occasional summer hosepipe ban, we have no shortage of water; this issue is likely to be more widespread in the future due to climate change. Our buildings and infrastructure need not only to save water but also to be more resilient to future extreme weather events such as storms and flooding.

We need to reduce potable water use to locally sustainable levels, which will of course vary dramatically between the regions of the UK. This can be achieved by reducing water use behaviour – practical steps can be made to reduce water consumption such as low flow fittings and appliances, or waterless appliances where appropriate, and better leak detection can be fitted as standard.

As a target, we need to work towards a reduction in potable water use by 60% to achieve a more sustainable level of below 60 litres per person per day for homes. We will need to use a greater quantity of recycled rainwater and wastewater and reduce potable water use for non-drinking purposes – simple and easy to maintain rainwater and greywater recycling and attenuation can have a huge impact on water use reduction, & where viable, onsite blackwater cleansing and recycling can also be considered.

More consideration will need to be given to waste water in general. Less wastewater discharge to local systems and less surface water run off leads to a reduction in the need for new wastewater treatment infrastructure. We will start to see much more stringent requirements for wastewater reduction in the UK soon. Sustainable Urban Drainage Systems (SUDS) are already in common usage, and these systems can be enhanced and used to support natural aquatic habitats and human amenities such as lakes, ponds, and wetlands.

There is a welcome trend to reinvigorate natural water courses that were often polluted and often built over in the past, and these can be championed in sustainable developments to create new habitats and good social value.

What is sustainable land use?

Biodiversity is declining at an alarming rate, both globally, as well as in the UK, whilst the need to create more new homes is growing.  

We need to focus on sustainable land use and avoid development on sensitive and ecologically rich sites. A scheme that is sustainable should leave the site in a better ecological condition than before the development, and whilst with consideration this is possible on almost any site, the most value added in ecology terms is provided where brownfield sites are redeveloped, and existing site pollution can be remedied. In urban areas, increasing biodiversity and the urban greening factor can also address the urban heat island effect of cities.

Developments should be mixed use where appropriate, and with a density appropriate to the local context. Opportunities for green space should be embraced, whether green roofs or vertical greening in urban sites, or pocket parks and green corridors in larger developments. New green spaces can be used to create habitats that enhance biodiversity and can also be used to create productive landscapes for urban food production.

A key target for all new developments should be to significantly enhance the local flora & fauna post development compared to pre-development levels

The need for sustainable transport and connectivity.

Transport operational carbon emissions account for approximately 25% of total UK emissions, which is is second only to buildings.

When choosing sites, it is obvious to say that priority should be given to selecting sites with good proximity to public transport. However, the biggest consideration in terms of sustainable transportation is car usage. Although 2020 was the first year on record that car ownership decreased, this is likely more due to the pandemic, rather than any long-term trend. In London, car ownership is at 0.74 per household – which is the lowest in the country, and in the Southeast, this raises to 1.41 – the highest.

For urban sites where proximity to public transport is available, car sharing spaces can make a valuable contribution towards reducing the need for car ownership. Sites where car parking is provided should provide the infrastructure for electric vehicles as a priority.

There are significant improvements being made to electric vehicles with 2040 being the current UK target for the switch over. This seems a long way off, especially viewed against countries such as Norway, who has banned the combustion engine from 2025, and where electric vehicles already account for 70% of new car sales, with a further 20% being hybrid. Norway does of course have significant hydro power resources to provide the clean energy required for these vehicles – in the UK, we will need to significantly increase renewable energy provision to power all these new electric vehicles.

Whilst we should of course reduce the long-term carbon emissions associated with transport and ensure that transportation links and parking provision are considered, more immediate change could be achieved by cutting the need for travel in the first place.

Increased physical and digital connectivity helps to avoid the need for unnecessary travel, and where it is required the journey time. Other measures such as the provision of high-quality pedestrian links to local amenities and suitable onsite personal storage are also valuable. In workplace schemes, end of journey provision for runners and cyclists such as showers and lockers also add value.

Sustainability, Good Health & Wellbeing

The buildings that we live and work in should be created to promote good health and wellbeingand should be inclusive, universally accessible, and adaptable to their occupants needs. Internal spaces should have a strong visual connection with the outside and provide responsive local controls such as openable windows. Air quality, daylighting, lighting, and thermal and acoustic comfort are all critical elements in creating good quality internal space.

At InsideOut, we use the WELL building standard, which is a performance-based system for measuring, certifying, and monitoring features of the built environment. It consists of features across its seven key concepts that address the design and operation of buildings and how they influence human behaviours related to health and wellbeing. The seven concepts can be categorised as air, water, nourishment, light, fitness, comfort and the mind.

An unintended consequence of the push for carbon emission reductions, and the focus on heat loss reduction, can be an increase in well-insulated and airtight buildings overheating in summer. Whilst a well-designed building will aim to design this out, this does demonstrate a point – that sustainability needs to be achieved holistically, with a focus on occupant health, as well as the environment.

What is social sustainability, and a sustainable community?

Social sustainability is “a process for creating sustainable, successful places that promote wellbeing, by understanding what people need from the places they live and work. Social sustainability combines design of the physical realm with design of the social world – infrastructure to support social and cultural life, social amenities, systems for citizen engagement and space for people and places to evolve(Social Life)

A sustainable communityis one that create a sense of place and encourages community interaction. Individual homes require the provision of a secure and private place, but this should be linked to a good quality public realm, where social and community interaction is encouraged and with links to social amenities. Where appropriate, vibrant and mixed-use places can, and should be created. The social impact of a development on the end users and the wider community can be considered as a social value benefit.

The aim of a sustainable development should be to create places for people that support not only basic needs of security, shelter, and health, but to enhance individual and social wellbeing, and community identity. In addition, the creation of jobs, training and apprenticeships through construction is also a valuable social benefit.

The WELL Community Standard applies the principles of the WELL building standard to a larger footprint with the goal of creating fully integrated and health-focused communities. It aims to impact individuals not just within the walls of their home or workplace, but throughout the public spaces where they spend their time.

WELL communities are designed to support health and wellbeing across all aspects and areas of community life. The vision for a WELL community is inclusive, integrated, and resilient, with a strong community identity fostering high levels of social interaction and engagement. Resources in a WELL community, natural, human, and technological, are used effectively, equally, and responsibly to meet the community’s current and future needs and priorities.

InsideOut’s approach to sustainable design

Let us be under no illusions – reducing the UK’s carbon footprint will be hugely challenging and costly endeavour. But what choice do we have? Climate inaction will also come at a huge cost. Potentially, there are huge opportunities for UK businesses, the economy and the construction industry in particular.

Going forward, when looking at the full life cycle costs of buildings – their construction, operation, and eventual demolition we will need to view this in the context of climate change. The running costs, ability to withstand climate change and resilience of buildings will need to be considered by construction professionals and building owners, as well, unfortunately, as the insurance industry.

There are obvious economic benefits in the creation of well designed, well-built, low carbon, and healthy buildings. More work does however need to be done to define the economic value of sustainability in the U.K – An understanding of the additional return on investment value created by the project, including rental value, building value, and social value.

The environmental movement seems finally to have the momentum to force wholesale changes, and housebuilders and building owners are going to need to adapt their businesses, or risk being left behind with a portfolio that will be difficult to sell, insure, mortgage and maintain.

There is an immediate and ongoing housing supply issue in the UK, but in our opinion, as people start to become more aware of the running, insuring, and retrofitting costs of inefficient housing stock, they will more and more drawn towards low-carbon, highly insulated and well-connected mixed-use development. The recent increase in energy prices and ongoing energy cost inflation will no doubt speed up this process. We could quite possibly face a similar situation with energy-use as we are with combustible cladding, where regulatory changes have rendered recently built homes un-mortgageable. To meet its 2050 Net Zero targets, the energy infrastructure of the UK will be moving from natural gas to low-carbon electricity, and this is bad news for poorly insulated homes that are reliant on gas boilers.

As well as increasing demand for low-carbon housing, the expansion of low-density suburban development will be curtailed. Planning policies will be expanding their focus on urban densification and brownfield sites centred around public transport infrastructure.

At site level, this will lead to a reduction in car ownership and mean that the space currently dedicated to roads, pavements and car parking can be put to more positive use: landscaped amenity, ecology, tree planting, greenspace, play space, community use, cycle lanes etc.

Our housing project in Saltdean was a stepping-stone towards this car-less utopia. While still accessed by road, residents park at the site entrance and walk to their front doors. With few dedicated roads, children have a safe, landscaped environment to play in and neighbourly interaction is facilitated – creating a community, not a dormitory.

This vision of the future is partially a picture of the past. A post-car, post-suburb, walkable, mixed-use future. A place where homes are grouped with workplaces, shops and amenities around landscaped areas, leaving space for nature to thrive.

It’s time for developers to consider the upcoming regulatory changes holistically, at the scale of neighbourhoods as well as buildings. The benefits are clear – future-proofed, desirable, dense, and cost-effective housing – in a fast-changing market, who will take up the opportunity and who will get left behind?