Ian Yenney reports on a research project giving valuable insights into low-carbon homes
Why isn’t every new home cost-effective to build and low-carbon in operation? This is the fundamental question that the Building for 2050 research project has sought to answer. What are the barriers and challenges to developing low-carbon homes and how can they be overcome? What are the design solutions, how do they perform, what do they cost, and what do the residents of low-carbon homes feel about them?
Low-carbon homes have been on the agenda for a long time. Successive updates to building regulations have improved performance standards in line with the UK government’s commitments in the Climate Change Act. Planning authorities have raised the bar further in some areas. Initiatives such as Zero Carbon Hub delivered excellent research and guidance a decade ago, while some housebuilders advertise their offering as already ‘green’. As we move towards the Future Homes Standard requiring a further performance improvement from 2025, you might be forgiven for believing that low-carbon homes are already ubiquitous, or soon will be. This is not the case.
The Building for 2050 research was commissioned by the then Department for Business, Energy & Industrial Strategy (BEIS)¹ in 2017 and delivered over five years by AECOM, supported by Pollard Thomas Edwards, Fourwalls and LCP Delta (incorporating Delta-EE). It has been supported by funding from the government’s £1bn Net Zero Innovation Portfolio, which looks to accelerate the commercialisation of low-carbon technologies and systems. The unique aspects of the research are its holistic socio-technical approach and the delivery team’s diverse experience. This is thanks to the way BEIS shaped the brief. Four low-carbon residential case studies were selected and reviewed from project inception to occupancy, with technical studies undertaken and stakeholder and resident views obtained. Wider industry and consumer surveys expanded and diversified the datasets, providing broader views.
What industry said
Industry stakeholders reported a variety of drivers for low-carbon homes. An early driver can be understanding the need to improve low-carbon performance and address fuel poverty issues. After that, a strong vision to deliver low-carbon homes is essential. Central government regulation and/or policy was considered the main driver by many. However, low-carbon vision may also be implemented locally, led by local authorities (for example, through ambitious carbon targets in local planning policy and on their own development sites) and supported by local business, thus developing a local supply chain and benefiting the local economy.
Financial drivers include grant funding for low-carbon technologies or advice, increased alignment of real estate investment with environmental, social and governance principles and manufacturer investment in low-carbon technology. Such collaboration can unlock low-carbon housing development.
Expert advisers can be instrumental in developing low-carbon designs and ensuring effective delivery on site. Grant funding for innovation needs to avoid encouraging complex designs that lose sight of the fact that these are homes, not experiments. Funding for low-carbon advice, maintained throughout the project, is likely to lead to better outcomes.
Numerous barriers to low-carbon home development were reported, including perceptions that low-carbon homes cost more to build. Uncertainty about future regulations, challenging market conditions and reluctance to change supply chains and improve designs were highlighted. Insufficient knowledge and skills, underdeveloped energy infrastructure (such as limited network capacity for all-electric homes) and concerns about consumer perceptions of innovative technologies were also raised. Industry seeks to understand the scale of changes needed, in order to plan and react accordingly. Masterplanning schemes now will deliver homes in 10+ years’ time, but the energy and carbon requirements are not yet known. Such issues result in industry inertia.
The typical absence of low-carbon homes reflects the drivers being too weak and the barriers too high. Industry, as well as central and local government, has a role in promoting the drivers and addressing the barriers. Industry also needs to ensure that the design performance is delivered in practice.
"It is important to understand how residents are getting on. Do they find the homes comfortable to live in, are they confident having a non-traditional home with non-conventional systems, and would they recommend others to live in homes like their own?” Alex Lerczac, social researcher, AECOM
What residents said
The main factors influencing homebuyers and renters are location, size, design, layout and price. Secondary drivers include lower energy bills², reduced environmental impact, warmth, comfort, good air quality, gas-free homes (considered safer as well as greener) and modern, high-quality homes.
Some of the barriers perceived by case-study residents before they moved in included capital cost, lack of availability and lack of awareness of low-carbon homes (including difficulty identifying them when searching). There were concerns about performance, reliability and maintenance of low-carbon technologies, about their appearance and the usable space they might take up, and about snagging issues and delays to project completion.
Residents provided in-depth accounts of the pros and cons of living in low-carbon homes. Reported benefits included warm and comfortable internal environments over winter, plus good air quality and ventilation. However, residents had to get to grips with new technologies and their controls and, in some cases, manage their daily routines to a greater extent. Despite an expectation for lower energy bills, often this was not experienced. Homes with low carbon emissions do not necessarily have low energy bills, owing to the cost difference between electricity and gas, while the performance gap can increase bills beyond design predictions.
Managing expectations is key. Despite some reservations, electric cooking was accepted. However, there were some negative experiences regarding hot water when supplied via heat pumps and storage cylinders. A better understanding of potential issues would lead to improved system design and handover advice.
"Although the Future Homes Standard planned for 2025 will be a major step towards delivering low-carbon homes, our research identifies further critical actions to support industry and the public, thus ensuring true low-carbon delivery and operation.” Alison Crompton, regional director, AECOM, and project technical lead
Findings and conclusions
The final report³ and four-page executive summary focus on increasing the supply and demand for low-cost, low-carbon homes and ensuring the delivery of intended energy and carbon performance. Updated building regulations will drive the requirement for lower-carbon homes. However, there is a risk that homes built to updated regulations will not perform as intended. Developers, design teams and site-based teams need to understand why and how in order to ensure as-designed performance is delivered; this includes placing greater emphasis on residents in early thinking and during the handover.
Knowledge sharing is also key. Achieving the UK’s net-zero commitments will require a focus wider than predicted operational carbon emissions. The research suggests this should include embodied carbon, assessment of performance in use, recognition of the dynamic carbon intensity of grid-supplied electricity and energy infrastructure upgrades.
Capital cost uplifts need not be a barrier to delivery. In well-planned, well-constructed low-carbon developments, typically with simpler designs, this uplift is minimal and could be cut further at scale. The main issue facing consumers is the lack of supply of low-carbon homes and readily available information about them. If developers have confidence in low-carbon home performance, promote the features and raise awareness, demand is likely to increase. Low-carbon homes must provide the positive experiences they are designed for. This requires a clear brief, focusing on a range of metrics, including low carbon emissions, running costs and comfort, improved design coordination, better site quality assurance and a comprehensive and tailored handover, including ongoing support. Attention to detail is critical from designers and builders: with lower heat loss targeted, missing insulation or poorer airtightness has proportionately greater impact than in traditionally built homes. Similarly, oversizing plant or poor commissioning can reduce efficiencies. Controls and advice need to enable occupants to understand and effectively manage their homes.
Greater industry upskilling and collaboration – from developers and design teams to planning authorities, those building homes and sales and handover teams – is needed to unlock low-carbon design and knowledge-sharing opportunities. Collaboration between developers and the energy services sector may reduce the cost of building and operating low-carbon homes and improve the resident experience.
Considerations for success
Ian Yenney, MESc(Hons), MIEMA, CEnv, is associate director, infrastructure & sustainability, AECOM
Footnotes:
1 Now the Department for Energy Security & Net Zero
2 The period of social research with residents, from 2018-2021, pre-dates the energy and cost-of-living crises, which may influence the priority given to drivers
3 The final report is available at www.buildingfor2050.co.uk and www.gov.uk/government/publications/building-for-2050
