Achieving Affordable, Modular, Net-Zero Carbon Housing
Ben Chaney and Dr Rehan Kohdabuccus discuss the commitment of ZED PODS to increase building energy efficiency and reducing embodied carbon emissions to meet UK’s net zero targets by 2050
With the UK government’s pledge to reduce emissions to net zero by 2050 and the UN’s sustainable development goals setting out a roadmap to inclusive and sustainable communities by 2030, the UK design and construction industries will need to make crucial adjustments to keep up.
A focus on increasing building energy efficiency, providing on site renewable energy and reducing embodied carbon emissions in order to meet these ambitious goals is a must.
ZED PODs are committed to delivering upon these goals and going beyond the timelines set to deliver net zero schemes today.
ZED PODs are a fully turnkey modular provider. We have designed and developed a factory-built modular construction system that can be used to assemble residential or commercial buildings, and is designed with an approach to holistically reduce carbon emissions and energy use. The steel-framed modular construction system has been designed with a fabric first approach to reduce operational carbon emissions by minimising thermal losses by conduction and infiltration.
The largest loss of energy in buildings is heat transferred from inside to outside. We reduce how much of this occurs by specifying thick insulation build-ups, insulated floor slabs and thermally-efficient triple-glazed windows and doors. A significant reduction in heat loss through the envelope by conduction is achieved with U-Values of less than 0.15W/m2.k for all elements. This is supported by robust, approved construction details and thermal breaks that reduce the thermal bridging and create a more uniform retention of internal heat.
Each module is provided with a dedicated airtightness layer and careful attention is paid around openings by use of taping to prevent warm air from the inside from escaping via infiltration and convection. We also use mechanical ventilation that recovers more than 80% of the heat from expelled air. This allows a constant supply of fresh air to circulate without the natural heat loss of other ventilation methods, and creates improved indoor air quality by reducing particulate matter and CO2 concentrations — while also increasing oxygen supply.
After reducing heat loss, our next strategy is to reduce the amount of energy used by occupants. During the design of our projects, we utilise simulation software to ensure that adequate daylight factors are created inside the spaces following the levels set out in BS EN 17037 — reducing artificial lighting and increasing solar gains. We then specify high performance A-rated appliances and water efficient fixtures and facets.
Once our build system has been designed and tested to the required efficiency, we use on-site renewable technologies to meet the energy demands. Hot water and heating demand is met via our MVHR unit and a solar assisted heat pump, which have no gas connections. The remainder of the energy need is met by roof-mounted photovoltaic panels, which offsets the remaining carbon emissions and results in a net zero scheme with a negative dwelling emission rate.
These modular design intentions are translated more effectively into ‘as built’ results, as the factory-built nature and standardisation of our modules ensures a more robust quality control system — which is approved by BOPAS and has been deployed across our design and construction system. The economic benefits delivered by our modular construction are a product of concurrent on-site and offsite works, lightweight construction and standardisation. This provides an affordable build cost that is near parity with conventional build systems, making it a viable solution for local housing associations, councils and homeless charities.
This is crucial, as the widespread adoption of more efficient build systems is the only way to reduce emissions across the industry. It also ensures that every unit is built to the same high standards without the need to compromise on performance to deliver high quality affordable housing for all.
Want to know more?
ZED PODS is funded by UKRI’s Transforming Construction challenge, aiming to accelerate the shift in construction towards manufacturing and digital processes and a value outcome approach. You can read more about what TCC does here.
About the authors:
Ben Chaney, Part-2 Architectural designer, ZED PODS
I’m a part-2 Architectural designer with experience in delivering projects from Feasibility to post planning stages. I have a background of work and study focused on sustainable design. My previous experience has been on a range of zero emissions developments from small scale development to master-planning. I specialise on sustainable building performance and design as part of my Architectural masters at Oxford Brookes. During this time, I developed a passion for reducing the industries impacts on the environment. I have been involved on a range of projects at ZED PODs helping to pioneer net zero carbon buildings as a standard for delivering affordable, attractive and practical new homes.
Dr. Rehan Khodabuccus, Operations Director — ZED PODS, Doctorate of Engineering (Eng. D), MSc (Distinction), BSc (Hons), Prince2 Practitioner MIET
A leading specialist in residential zero carbon buildings, equipped with a unique combined technical, scientific and economic background developed over 13 years of working within the construction sector, Rehan became Operations and Technical Director at ZED PODS in 2018. A highly skilled technical and operational specialist adept at delivering low carbon commercial and residential building specifications, Rehan is adept at developing technical and economic models that prove commercial viability for low carbon technologies, construction solutions and residential developments. Rehan has completed a Doctorate in Engineering (Eng. D), an MSc in Environmental Strategy (Distinction), qualified as a ‘’Prince 2 Practitioner’ Project Manager and Member of the Institute of Engineering and Technology. Rehan has also delivered key components of 2 complex EU ‘Seventh Framework Programme’ for Research (FP7) Projects and is currently instrumental in delivering an Innovate funded Transforming construction project. He currently specializes in developing net zero carbon housing projects using offsite manufactured homes.