The BSRIA LSBU Net Zero Building Centre

Accelerating a decade of action on decarbonisation in the built environment.

BSRIA logo

The Net Zero Building Centre is a joint venture between BSRIA and LSBU.  It was created to be an innovation hub and centre of excellence that builds on the shared strengths of BSRIA and LSBU in field of low carbon buildings.

The Building Services Research and Information Association (BSRIA) is a non-profit distributing, member-based association promoting knowledge and providing specialist services for construction and building services stakeholders. Their mission is to make buildings better by improving their environmental, operational and occupational values, and to support the industry by providing guidance and solutions.

LSBU has world leading expertise in the built environment, drawing on decades of academic and applied research experience in Energy, Civil and Building Services Engineering, Modelling and LSBU’s solid and long-standing professional reputation in the construction and property industry.

The BSRIA LSBU Net Zero Building Centre brings this background and expertise to the urgent issue of mitigating the impacts of the built environment on climate change.  The majority of the world is signed up to the Paris Climate agreement, which aims to limit global temperature increase to 1.5°C above pre-industrial levels.  To do this, we need a Net Zero carbon economy by 2050.

The built environment has a critical role to play achieving this transition and the Net Zero Building Centre aims to accelerate a decade of action on decarbonisation.  This includes increasing the uptake of the solutions we already have, and creating world leading innovation to find the breakthroughs we need.

Within this broader goal the Net Zero Building Centre focuses on the following areas:

Decarbonisation of heating and cooling

Smart Building Performance

Indoor Environmental Quality

Policy Implementation

Our Centre draws together members from BSRIA and LSBU who are dedicated to sustainability in the built environment. Members bring their experience of impactful, applied research and working with an array of industrial and academic partners to drive the Centre’s vision. Early career researchers work with experienced colleagues to gain the skills and knowledge they need to achieve significant environmental, social and economic benefits in the field.

Staff directory

The BSRIA LSBU Net Zero Building Centre

Bridgend - Local Energy Markets


Bridgend County Borough Council (BCBC) has actively pursued a decarbonisation agenda for several years. Through their involvement in the Smart System and Heat Programme BCBC they developed a Local Area Energy Plan creating a pathway for decarbonisation in Bridgend. The Local Area Energy Plan included funding a Local Energy Market competition within Bridgend to create projects that could build the tools necessary to accelerate the pathway to net zero carbon in Bridgend.  The consortium of ICAXCambridge Energy, and the BSRIA LSBU Net Zero Building Centre were among the successful projects chosen to test innovative options for Local Energy Markets in Bridgend Council.

Local Energy Markets

The project partners contributed collaborative research into how the newly formed local energy market could operate optimally to further the delivery of a Net Zero Bridgend and offer a template for decarbonisation across Wales. Researchers investigated how heat pumps could fit into the local energy market and possibly connect to local wind energy generation.  The overarching goal of the project was to define the circumstances for which heat pumps would be an optimal low carbon heating source for homes in Bridgend.

This was done through considering a variety of circumstances in different combinations, including, housing types, energy prices, and the package of technical measures accompanying the heat pump.

Cambridge Energy modelled the costs and benefits of different types of low-carbon heating in Bridgend.  The BSRIA LSBU Net Zero Building Centre carried out a stock assessment that included archetyping, pricing, and monitoring options. And ICAX created a bespoke low carbon heating option by evolving their current heat pump product range.

Cost Optimisation (Cambridge Energy)

Part of this broader research was focussed on the investigation of what impact different forms of low-carbon heating had on cost, energy use and carbon emissions. Specialists from Cambridge Energy have developed the Cost-Effective Domestic Electrification (CODE) models on behalf of the UK Government’s Department for Business, Energy, and Industrial Strategy (BEIS). CODE uses the EnergyPlus engine to perform dynamic simulations of 12 distinct house archetypes that represent ~90% of UK homes.  Optimisation iterates 14 different heating systems and combinations of retrofit measures to enable those systems. CODE uses this information to establish the cost optimal combination of heating and efficiency measures for each archetype.

For this project, the CODE models were calibrated to the Bridgend housing stock, and updated to include a range of energy pricing options from local renewables generation.  It was also updated to include the performance details of the bespoke heat pump developed by ICAX as part of this project.

Local Stock Factors (BSRIA LSBU Net Zero Building Centre)

This work consisted of defining inputs to support both the CODE modelling and the heat pump development.  The CODE models use 12 archetypes to represent 90% of UK homes.  This project used a combination of data sources to update the distribution of these archetypes based on the local stock within Bridgend.

LSBU also carried out a desktop research exercise to establish the range of potential electricity prices that could be available through the use of local renewable generation and private wire connections.  The CODE models were already set up to utilise the Octopus Agile tariff and this was modified according the findings of this research to reflect the likely energy prices for a potential Local Energy Market in Bridgend.

Finally, BSRIA designed a monitoring and evaluation strategy that could be used to test and validate the CODE modelling assumptions in situ should the Council choose to implement these in actual homes.  This also included plans for an evidence base of user engagement factors including underexplored comfort factors such as the acoustic performance of the heat pumps.

Heat Pump Design (ICAX Ltd)

The overarching goal of the project was to define the circumstances for which heat pumps would be an optimal low carbon heating source for homes in Bridgend. High temperature air source heat pumps were identified as being suitable for the in-house installation. Their higher temperatures are cost-effective due to them not requiring larger radiators being installed, as is the case with low temperature heat pumps. This would limit the number of additional measures such as insulation and radiator replacements required to make the system viable, keeping costs down whilst saving space and hassle.

The CODE modelling output indicates that high and low temperature air source heat pumps are optimal in several circumstances, and that only modest fabric upgrades such as top up loft insulation and draught stripping are required to maintain comfort and performance.


CODE final report (


Small Business Research Initiative (SBRI) – Affordable Urban Heat Networks


The Caerau Heat Scheme in Bridgend, Wales is a highly innovative project that sought to provide low-carbon heat to properties in Caerau.  The overall aim of the scheme was to demonstrate alternatives to fossil fuel heating that could reduce carbon emissions as part of a scalable approach to developing local supply chains for a low carbon economy.  It also sought to address fuel poverty and health inequalities among residents by investing in upgrading homes.

The original proposal was to extract heat from water contained in a disused coal mine, and Bridgend Council obtained funding to carry out a series of feasibility studies.  The studies found that the scheme might be technically feasible but practically challenging and costly to implement.  The consortium of ICAX LtdCambridge Energy, LSBU and BSRIA were among the successful applicants in an SBRI Affordable Heat Networks competition to explore innovative options for cost reduction and design flexibility.

Affordable Heat Networks

The project was based on creating a flexible heat pump product that could be integrated into Caerau but also function independent of the mine water network if this was cost optimal.  This would allow properties in Caerau to have flexibility in phasing their transition from gas to low carbon heating using the mine water heat network as the preferred option, but without disruption of service for homes where the mine water network was not technically or economically feasible.  The work was divided among the partners: heat pump product development (ICAX Ltd), local market investigation (Cambridge Energy), building performance and monitoring (BSRIA and LSBU), and grid optimisation modelling (LSBU).

Heat Pump Product Development (ICAX Ltd).

Heat pumps typically come in two types: air source heat pumps are lower in installed cost, while ground source heat pumps have higher performance. ICAX Ltd had previously collaborated with LSBU on the Home Energy 4 Tomorrow (HE4T) project, which created a field prototype dual source heat pump (DSHP) that could toggle between air and water heat sources.  The DSHP is capable of using the mine water (or any other ground source) for heat, or switching to air source mode when the heat sink is depleted without any interruption in service to the end user.  This arrangement delivers a similar performance to a ground source heat pump, but with around half the ground heat exchange area.  This dramatically decreases the cost of the unit, meaning that it can deliver the performance of a ground source heat pump at a lower cost.

For this project, the Dual Source Heat Pump field prototype was refined into a commercial product that could be deployed in Bridgend County Borough or any home across the UK. The work consists of refining the controls, assembly, and appearance of the heat pump, testing it in LSBU laboratories, having it certified in BSRIA’s test centre, and deploying it to a pilot home in Bridgend.  Additionally, an air source heat pump is being installed in a similar home for comparison.  Both heat pumps will be monitored in situ for one year.

Local Market Investigation (Cambridge Energy)

Cambridge Energy carried out semi-structured interviews with heating installers located less than 40 miles from Caerau in South Wales. They asked them what experience they had installing heat pumps, whether they were prepared to go through training, what electrical qualifications they had, and how much they charged. They also asked them if they would be confident in helping to install heat pumps in Caerau.

The majority of installers said they had prior experience of installing heat pumps in homes. One of the installers had already installed a heat pump using mine-water as the heat source. All of those with prior experience installing heat pumps said they would potentially be interested in helping to install heat pumps at Caerau, and they were confident they could assist.  Those with no experience installing heat pumps did not express interest nor were they prepared to undertake training to acquire skills in heat pumps.

The research is also engaging the homeowners in both of the demonstration homes in order to explore satisfaction with comfort, homeowner engagement and preferences with the low carbon heating systems.

Building Performance and Monitoring (BSRIA and LSBU)

Heat pumps have a higher performance at lower operating temperatures. In some cases, swapping gas boilers for heat pumps may lead to the requirement of fabric and heat emitter upgrades to compensate for lower temperatures from the heat source. The researchers conducted a parametric modelling exercise exploring the conditions under which reduced distribution temperatures could still deliver comfortable conditions on a peak cold winter event.

The broad finding of this modelling study is that many rooms would be sufficiently comfortable even with cooler radiators by extending operating hours.  Often adding a small amount of wall insulation (10mm) allows a further reduced distribution temperature (cooler radiators) and increased heat pump performance without sacrificing comfort.  A deep retrofit (125mm wall insulation) allows considerable flexibility with both heating system timing and distribution temperatures without sacrificing comfort.

However, in almost all cases, there were cold rooms that required additional measures. This was true even in the baseline case, with a gas boiler and 70°C radiators. Many people have at least one cold room in their house despite gas central heating. This means that the low carbon heat transition in Caerau (as with much of the UK) is an opportunity to address longstanding fuel poverty issues and the associated comfort and health challenges.  There is also a high likelihood of comfort takeback following the installation of any measures, which must be considered in forecasting the demand for low carbon heat.

Given the variability of the results within a single home, the most effective path to getting low carbon heat will vary by home, and even from room to room within the home.  This study suggests that where site constraints limit what is practically possible, a room-by-room approach can offer cost reductions by finding the optimal path to comfortable low-carbon heat within an individual home.

BSRIA is carrying out detailed onsite monitoring of the demonstration homes to test and validate these modelling predictions and also feedback these results into the design of both the heat pumps themselves, and the cost optimal combination of retrofit measures to best enable the heat pumps to perform as effectively as possible for these types of homes.

Grid optimisation modelling (LSBU)

Electrification of heating is desirable for sustainability reasons (since, ultimately, carbon emissions will be lower, and urban air quality will improve), but potentially problematic for the electricity grid which is already under great demand. Ideally, increased electrification of previously fossil fuelled technologies will occur without having to expand the grid due to resource and time constraints. Avoiding the expansion of the grid requires reduced energy demand which, in the case of home heating, is achieved through retrofit to improve energy/ thermal efficiency.

This research is developing a digital grid twin in Matlab to investigate the behaviour of the electricity grid and real time operation of the network operator. The digital twin grid provides an indication of the overall impact on electrical demand through the day, should all Caerau dwellings be converted to electric heating. Understanding the effect on the grid, allows for planning to alleviate pressures posed by the electrification of heat in Caerau.

Staff Links

The Net Zero Building Centre members have delivered a wide range of successful projects including:

  • The Balanced Energy Network (BEN) innovative industry and academia collaborative research project shortlisted for the Engineer: Collaborate to Innovate Awards, 2018.
  • The Home Energy 4 Tomorrow (HE4T) project designing and testing a hybrid heat pump and looking at heat recovery from water utilities.
  • The Affordable Heat Networks Project in Bridgend County council which exploring how a dual source heat pump can offer cost reduction options for a Mine Water Heat Network.
  • The Net Zero Innovation Programme with Lambeth Council exploring the skills gaps and local supply chain needs to respond to the climate emergency goal of creating a carbon neutral council by 2030.

The Net Zero Building Centre is a joint venture between BSRIA and LSBU and benefits from their shared expertise as well as their extensive networks across the built environment.

We have a number of strong research collaborations and partnerships as well as established links with governmental and professional bodies.

The Net Zero Building Centre works closely with other research centres within LSBU including CCiBSE and IDOBE.

The centre through its members has strong links with the various subjects area professional bodies including:

  • The Chartered Institute of Building Services Engineering
  • Energy Institute
  • The Institute of Refrigeration
  • The Institute of Acoustics
  • The Institution of Civil Engineers
  • The Institution of Structural Engineers

The centre also has reach portfolio of working with industrial partners in research and consultancy. These include:

  • ICAX Ltd.
  • Cambridge Energy

We are also actively engaged on projects with Lambeth, Southward, and Bridgend Councils.