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Achieving Affordable, Modular, Net-Zero Carbon Housing

Posted: 23rd November 2021

Ben Chaney & Dr. Rehan Khodabuccus

Part-2 Architectural designer (Ben) & Operations Director (Rehan)


With the UK governments 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 focus on increasing building energy efficiency, providing on site renewable energy and reducing embodied carbon emissions in order to meet these ambitious goals.

ZED PODs are committed to delivering upon these goals and going beyond the timelines set to deliver net zero schemes today. The award-winning net-zero-carbon social homes project “Hope Rise”, built above a public car park in Bristol, was showcased by the UKGBC at the COP26 virtual pavilion for built environment along with 16 other sustainable projects across the globe.

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.

Firstly, we reduce how much heat is transferred from inside to outside (the largest loss of energy in buildings) 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 for all elements 0.15W/m2.k. This is supported by robust approved construction details and thermal breaks that reduce the thermal bridging and creates a more uniform retention of internal heat.

Each module is provided with a dedicated airtightness layer and careful attention is paid to airtightness's around openings by use of taping to prevent warm air from the inside from escaping via infiltration and convection. We use mechanical ventilation that recovers more than 80% of the heat from expelled air meaning that there is a constant supply of fresh air circulating without the natural heat loss of other ventilation methods. This also results in improved indoor air quality by reducing particulate matter and CO2 concentrations (which can lead to fatigue) and 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. Where possible we encourage the

Once our build system has been designed and tested to the required efficiency, we use on site renewable technologies to meet the energy demands. For hot water and heating demand via our MVHR unit and a solar assisted heat pump. Our units have no gas connections and so the remainder of their energy is met roof mounted photovoltaic panels. This offset the remaining carbon emissions resulting 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 we have deployed across our design and construction system and is also approved by BOPAS. The economic benefits delivered by our modular construction are a product of concurrent onsite 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.

Ben Chaney & Dr. Rehan Khodabuccus

Part-2 Architectural designer (Ben) & Operations Director (Rehan)


Ben Chaney is a Part-2 Architectural designer at ZED PODS and Dr. Rehan Khodabuccus is Operations Director at ZED PODS. ZED PODS is the British leading accredited specialist in modular built homes over car parks & land that cannot otherwise be developed.