Designing for net zero and beyond

The transition to net zero housing is no longer a distant ambition. A recent roundtable discussion, hosted by Polypipe Building Services, brought leading architects, specifiers and developers together to examine the challenges and solutions in designing sustainable homes. Specify & Build reports. 

 One of the most pressing discussions during the Polypipe round table centred around the UK’s ambitious net zero targets and the growing role of heat pumps in achieving them. The Climate Change Committee has projected that, by 2040, half of UK homes will need to be fitted with heat pumps. While participants acknowledged heat pumps as a crucial part of the solution, they questioned whether they are the only viable option. Many agreed that a fabric-first approach – where buildings are designed with high thermal efficiency – should be prioritised to minimise energy demand before considering heating technologies. 

Ventilation also emerged as a key component of the net zero conversation. As homes become more airtight to improve efficiency, proper ventilation is essential to maintain indoor air quality and prevent damp issues. Mechanical ventilation with heat recovery (MVHR) systems were highlighted as a promising solution, allowing homes to retain heat while ensuring fresh air circulation.  

Passive ventilation strategies were also discussed as an alternative approach. Design elements such as strategically placed vents, green walls and natural airflow systems can significantly improve indoor air quality without relying on energy-intensive systems. Some architects are exploring ways to integrate these features into new developments, balancing energy efficiency with occupants’ health and wellbeing. 

Embodied vs. operational carbon 

Another hot topic was the balance between embodied carbon (the emissions associated with materials and construction) and operational carbon (the emissions generated by a building’s use). While operational carbon reduction has been the primary focus in past years, there is increasing recognition that embodied carbon must also be addressed. 

A growing trend among architects is to prioritise the reuse of materials wherever possible. The idea of circular construction – where buildings are designed with future adaptability in mind – was discussed as a way to reduce waste and extend the lifespan of building materials. Some are even exploring ways to reclaim and repurpose steel beams, bricks, and insulation from demolished structures. 

Furthermore, the importance of integrating whole-life carbon assessments into the design and construction phases was highlighted. By measuring the full carbon impact of a building from production to demolition, developers can make more informed choices about material selection and sustainability strategies. Many participants emphasised that embedding carbon measurement into regulations would be a critical step in driving industry-wide change. 

One particular challenge noted was the perception that sustainable materials come at a premium. While some eco-friendly options may have higher upfront costs, they often lead to long-term savings in terms of energy efficiency and maintenance. More education and awareness is needed to shift mindsets and highlight the benefits of investing upfront in sustainable materials. 

While heat pumps dominated much of the discussion, alternative renewable energy solutions were also explored. The potential of district heating networks, particularly in urban environments, was identified as an underused resource. By pooling heat from multiple sources – including waste heat from industrial processes – district heating can provide a more efficient and scalable solution for low-carbon heating. However, participants noted that many local authorities are lagging in their planning for such systems, creating missed opportunities for large-scale decarbonisation. Another potential avenue for reducing carbon emissions in homes is the integration of hybrid heating systems. These systems combine heat pumps with other low-carbon technologies, such as solar thermal collectors or hydrogen-ready boilers. By using multiple energy sources, hybrid systems can offer greater resilience, particularly in colder months. 

Overcoming the skills shortage 

A major roadblock to delivering net zero housing at scale is the industry-wide skills shortage. Installing heat pumps, designing and maintaining MVHR systems, and ensuring airtightness in buildings all require specialised expertise that is currently in short supply. Participants highlighted the need for more investment in training and apprenticeships to build a workforce equipped for sustainable construction. 

One proposed solution was increasing the use of off-site manufacturing and modular construction. By assembling key building components in controlled factory environments, companies can improve quality, reduce waste, and minimise on-site labour requirements. Some developers are already leveraging this approach, producing pre-fabricated mechanical and electrical systems that can be quickly installed in new homes. Additionally, early collaboration between manufacturers and developers can help address knowledge gaps and ensure that sustainable solutions are incorporated effectively. Engaging with product suppliers at the design stage can help architects and engineers identify the best materials and technologies for reducing a building’s carbon footprint.  

Is Government doing enough? 

The discussion also touched on the role government policy will play in net-zero housing. While the Future Homes Standard is set to come into effect, many in the industry feel that current regulations do not go far enough. Participants agreed that the government should take a stronger stance in incentivising the use of low-carbon materials and setting clear, enforceable targets for reducing embodied emissions. Another concern was the financial burden placed on developers to meet sustainability standards. While green finance options are emerging, including sustainability-linked loans and green mortgages, the industry still faces significant cost barriers. Some participants called for greater financial incentives, such as tax breaks or grants, to support the transition. 

The role of water management 

Beyond energy efficiency and heating, another crucial aspect of sustainable housing is water management. Climate change has led to an increase in extreme weather events, with heavier rainfall and longer droughts becoming more common. This places additional pressure on urban drainage systems, necessitating smarter solutions for water retention and distribution. 

Blue-green infrastructure – such as rain gardens, permeable pavements, and green roofs – was identified as an effective strategy for managing water in urban developments. By integrating natural water absorption and filtration systems, buildings can reduce the risk of flooding while also creating more pleasant and biodiverse environments. 

Water recycling technologies, such as greywater reuse and rainwater harvesting systems, were also discussed as viable solutions for reducing potable water consumption. Some new housing developments are beginning to incorporate these systems, allowing non-drinking water to be reused for toilet flushing, irrigation, and even laundry, thereby reducing demand on mains water supplies. 

The importance of retrofit 

While much attention is given to newbuild developments, the UK’s existing housing stock presents one of the biggest challenges for net zero goals. Many older properties are highly inefficient, leading to excessive energy use and high emissions. Retrofitting solutions such as better insulation, draught-proofing, and upgraded heating systems, are essential in bringing these homes up to modern efficiency standards. 

One promising approach is the integration of heat networks into retrofit schemes. By connecting multiple properties to a centralised low-carbon heat source, existing homes can benefit from sustainable heating solutions without requiring costly individual system overhauls. 

Despite the challenges, there was a strong sense of optimism that the industry can and must work together to drive sustainable change. The roundtable underscored the importance of early collaboration between architects, specifiers, manufacturers and policymakers to ensure that sustainability is embedded into projects from the outset. 

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The round table attendees were: 

• Danielle Michalska, Barratt Redrow

• Amelia Charman, Wandle Housing Association 

• David de Sousa, AHR Architects 

• Louise Scannell, WW+P Architects 

• Kerry Heath, Hexagon Housing Association 

• Kate Watson, Turner & Townsend 

• Michela Ravaglia, Wates Group 

• Jennie Ward, Specify & Build 

• Gavin Robinson, Polypipe Building Services 

• Adam Pointon, Geniut Group  

• Simon Mason, Polypipe Building Products 

• Chris Smith, Polypipe Building Services 

• Hayley Hayes, Polypipe Building Products 

• Jakes Parker, Architects’ Datafile. 

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