Low cost, Low Carbon Homes:
Building for 2050 offers a snapshot of the UK’s construction industry and its ability to deliver low-carbon homes now. It identifies how best to minimize cost, improve energy efficiency, reduce carbon emissions, increase consumer demand, and accelerate industry delivery of low-carbon housing. While the focus is new building housing in England and Wales, the key findings broadly apply to all new building housing throughout the UK.
Building for 2050 is unique research. A detailed analysis of case study projects, it identifies the barriers and opportunities to their delivery at scale and examines the impact this could have on energy demand and carbon emissions.
It provides a rounded analysis of the whole process from inception to occupancy – developing, designing, constructing, and living in low-cost, low-carbon homes. This holistic evaluation incorporates the views of multiple stakeholders and draws upon case study homes, the wider construction industry, and the energy services sector. A wide-ranging consumer survey and a general industry survey further contributed to the findings.
If all homes constructed in the future are built to a low carbon standard, there should be no need to retrofit these homes before the UK Government’s net zero 2050 deadline. The project was led by AECOM and supported by Pollard Thomas Edwards (PTE), Four Walls, and LCP Delta (incorporating Delta-EE).
This five-year project – begun in 2017 and completed in 2022 – investigated low-carbon housing to understand why and how this type of home is being built, how the residents use energy, and what their experiences are. It also sets out to understand how the construction industry can deliver low-cost, low-carbon homes on a large scale, and asks – what are the drivers and barriers shaping this emerging sector?
The report is informed by literature and market reviews, four in-depth case studies of low-carbon housing schemes across England and Wales, and surveys and interviews with technical and consumer audiences.
The case studies focussed on:
• Interviews with development teams on the delivery of low-carbon homes
• Interviews with residents sharing their expectations and experiences with living in their homes. This covered energy bills, comfort, and the usability of low-carbon technology.
• A design review of homes and site observations during construction and post-completion on the buildability of the designs;
• An assessment of additional low-carbon capital costs;
• Post-completion testing of the thermal performance of building envelopes and mechanical ventilation systems;
• A comparison of the SAP (Standard Assessment Procedure) modeling undertaken by the development teams and the research team;
• Monitoring of the energy and environmental performance of homes in use;
• Consideration of the operation of the homes in a changing energy system.
Today, no major housebuilder is building low-carbon homes at scale. For this reason, the case studies focus on low-carbon projects undertaken by small- and medium-sized developers. The four developers had different funding models and approaches to low-carbon design. These factors, combined with the mix of tenures, provided a good range of research data. Marmalade Lane Cohousing, Cambridge provides 42 dwellings, a mix of flats and houses, with a shared ‘Common House’ facility.
Active Homes, Neath, Wales provides 16 homes, a mix of houses and flats for social rent. Ectopia Homes, Corby, Northampton shire provides 47 homes, flats, and houses, for private sale.
Tallack Road, Waltham Forest, London is a private development providing a mix of 80% private and 20% affordable homes in 48 flats and two houses.
Case study residents had an expectation of lower energy bills, although for many of them, this wasn’t the case in practice. A focus on running costs at the design stage, design simplification and better coordination, greater on-site experience, and improved handover processes will help to mitigate this.
There were other benefits, however: residents reported warm and comfortable internal environments and good air quality and ventilation in their low-carbon homes.
Around half felt their homes imposed constraints on their behavior. Getting to grips with technology, learning how to optimize controls, and then adapting how you live to suit, takes time. Some residents had to manage a daily routine around the reduced availability of hot water. Early consideration of the residents, focusing on the daily operation of homes, and informed advice will help to address this in future homes.