Retrofitting to net-zero

The race for energy efficient homes and buildings
According to the World Green Building Council, the building construction sector and use of buildings is responsible for 39% of global energy-related emissions. In the UK, 80% of homes required in 30 years’ time have already been built(1) and with existing buildings in the UK responsible for 19% of annual emissions,(2) the focus is on reducing the amount of energy being used by the existing stock of underperforming buildings.(1)

The UK is one of many countries committed to achieving net-zero carbon emissions by 2050. It is clear that this goal isn’t attainable without the creation of net zero homes. (3)

Achieving net-zero seems an almost impossible task but what is clear when it comes to construction is that the carbon impact of a building’s entire life must be considered, as well as the needs of the occupants. i.e looking at both the fabric of the building and its performance, as well as meeting the need for clean air, light, warmth and privacy.

New residential design and build considers the whole environment and entire lifecycle of the building from the outset, but more than a third of building emissions are created during the construction process. In addition, the very process of making materials and their transportation to a final destination is expensive, so cost, but more to the point the energy demand from existing stock are the main drivers to upgrading rather than building new.

“..for every dollar spent on reducing the energy consumption of buildings on the demand side of the energy equation, saves the need for two dollars spent on expanding the supply side of the equation.” (4)
Wagdy Anis, FAIA, LEED AP, Chairman BETEC Board, Chairman JBED Editorial Board

Challenges to retrofit
Many of the ideas for retrofitting buildings have already been proven including upgrades to insulation and improved thermal performance through energy efficient windows, thermal insulation and increased air tightness, more efficient electrical and heating appliances and more effective building management systems.

It was encouraging that some of the renewable technology for sourcing and storing heating made an impact. Sales of heat pumps and renewable heating equipment such as solar hot water systems increased up to 2019, but to date we are still relying on fossil fuels for suppling more that 55% of final energy consumption.(5) In fact, fossil-fuel based equipment and conventional electric heating technologies constitute almost 80% of new sales.(6)

An inquiry led by the Business, Energy and Industrial Strategy Committee – a select committee of the House of Commons – found the rate of installation of efficiency measures in UK buildings under government schemes has plummeted by 95% since 2012.(1)

Only 4% of architects in a recent Retrofit survey by WSP saw ‘a very high improvement in average energy efficiency in their retrofitted building over the last five years’.

Smart home technology is already used in many homes to keep track of the energy we’re using and when to help us attain energy saving goals, but these devices themselves require additional energy.

Conex Bänninger - retrofit to net-zero

Moving from fossil fuel to electricity and smarter homes
According to the Carbon Coop, a prominent route to net-zero housing in the UK is the move of domestic heating away from gas and oil, and into electricity; heat pumps rather than gas boiler.(8)

With this move, the consumption of electricity in the residential sector is set to grow with electrification of heat bills rising by as much as 70%. Once renewable energy becomes part of our energy sources and is managed through intelligent smart meters or hubs, our awareness of consumption can be better managed.(3)

Smart products in the home are not new, but we are moving away from devices that help us control energy room by room, to technologies that can give us more data and energy insights as well as autonomous and smart consumption. Add artificial intelligence and machine learning and the smart home will be able to identify best energy sources at the right time to reduce cost. The potential is there to reduce energy consumption and electrical heating costs by up to 50%.(3) This only solves part of the problem in that renewable energies have to be part of our energy sources and homes have to be readied for the changes.

Industry leaders feel that there is a fragmentary approach to installing energy-saving measures which is not going to help the UK reach zero-carbon, and what is needed is a change to the approach of achieving the net-zero emissions target,(9) one that encompasses whole of system, as well as government, finance, law and technologies.

Whole of system thinking
In a letter to the prime minister in 2019, the Council for Science and Technology stated that ‘Achieving net-zero will require fundamental changes in our society and economy’ and that ‘a whole systems approach’ would be needed to deliver a better transition towards targets. This would encompass four fundamental areas; central government structure, the analysis and flow of information as well as the contribution of technology, financial systems and international collaboration(7).

The legal structure for decarbonisation is in place, but what is needed is an equally strong and effective structure inside government. The proposal outlines the challenges raised by net-zero targets and gives decisions makers the whole information needed to devise solutions and innovations that have more chance of succeeding(10).

Whole of building
There is a need for homeowners to reduce energy consumption and this will largely be driven by cost, but also to adopt more sustainable energy sources. Homes have been altered and adjusted over time but may end up with a mix of features and technologies that don’t necessarily work together efficiently. For example, an improvement involving draughty wooden window frames replaced with modern PVC or PU options, may have an effect on ventilation causing a build-up of moisture leading to humidity and the risk of damp and mould.

A better approach is ‘deep-retrofit’ or whole of house retrofit which creates a zero-energy home in one step and has the potential to reduce carbon emissions in 41% of UK housing stock. Whole house retrofit encompasses a series of remedies that work in synergy with each other to achieve net-zero whilst providing occupants with everyday comfort.

Leading energy and services organisations like Engie aim to develop and produce a single retrofit solution with integrated fabric upgrades, mechanical and electrical and monitoring components with the final solution built off-site and manufactured at scale.

Whole system and deep retrofit in practice
Energiesprong (energy leap) Foundation’s approach to whole house retrofit was first piloted in the Netherlands and works across the system, attracting funding through several supporting European projects. They work with regulators on policy and regulations, as well as banks to enable them to scale projects up to large volume retrofits making them cheaper(11).

According to Green Alliance, Energysprong provides the route to a large-scale heating solution for the UK. The net-zero home is typically achieved by:

A new thermally efficient façade, which creates an airtight and insulated shell around an existing property.
A solar PV roof sized to generate as much energy as the property consumes.
An energy hub, with air or ground source heating and optional batteries, which enables the home to provide energy services to the grid(12).

This concept creates a net zero home at one time unlike other approaches like Passivhaus which works in a step-by-step way with whole house retrofit. It also makes the home extremely affordable to run as each refurbished home produces enough clean energy to meet its own heating, hot water and electricity needs. The initial retrofit costs money but balancing the scales of the cost of the work is what money would normally be spent on bills.

According to Energiesprong UK head of team, Emily Braham, ‘there are 11m older, hard-to-heat homes in the UK that could be retrofitted to the net-zero standard with existing technology. Today the cost is too high, but once 40,000 retrofits are in the pipeline – which is the plan by 2030 – costs can halve. It would then be entirely possible to self-finance high-volume, low-carbon makeovers from energy and maintenance savings’.(9)

Financial incentive schemes
Whole property retrofit can be encouraged with the right financial incentives such as the one initiated by KfW Development Bank in Germany. The scheme provides loans at low interest rates to cover capital costs and has been successful in seeing over 250, 000 homes receiving funding and saving 730,000 tonnes of emissions.

The additional benefits are the huge number of jobs created and the return on investment in tax receipts and savings.(13)

Where to from here?
In July 2020, the government announced a £50m pilot scheme to kick-start a national retrofitting programme for social housing tenants. But according to Nicholas Harris, Chief Executive of Stonewater, this only just begins to address what needs to be done – given the scale of the challenge. The proposed budget will only cover a fraction of the UK’s social housing tenants and reach only the very worst performing stock.

The responsibility for delivering net zero and retrofitting homes doesn’t just lie with government. Social enterprise, business, investors and consumers are involved, but most initiatives will not achieve net zero without government backing.(15)

A whole system approach, working in synergy can make our homes more efficient, and deliver the retrofitting programme our country needs. Making UK housing net zero can be achieved together(15) – and tackled in the right way can deliver better homes, healthy occupants and be cost effective. (15)

REFERENCES:

General reference: https://www.ukgbc.org/climate-change/

FURTHER READING

About WSP
WSP is one of the world's leading engineering professional services consulting firms. We are dedicated to our local communities and propelled by international brainpower. We are technical experts and strategic advisors including engineers, technicians, scientists, planners, surveyors and environmental specialists, as well as other design, program and construction management professionals. We design lasting solutions in the Property & Buildings, Transportation & Infrastructure, Environment, Industry, Resources (including Mining and Oil & Gas)
www.wsp.com/uk

About UKGBC
UKGBC is uniting the UK building industry using sustainability as a catalyst to positively transform the places people use every day. A charity with over 400 member organisations spanning the entire sector, we represent the voice of the industry’s current and future leaders who are striving for transformational change.  UKGBC was launched by the construction and property industry at the Ecobuild exhibition in London in February 2007. We were originally established to offer clarity, cohesion and leadership to a disparate sector, and to campaign for a sustainable built environment. We were set up with the invaluable help and commitment of a core group of founding members many of whom are still active members today.
www.ukgbc.org

About NetZero initiative
Net Zero Initiative, for a challenging corporate carbon neutrality
Net Zero Initiative is a space for innovation and actions for a challenging, credible and ethical carbon neutrality. Created by the French consulting firm Carbone 4, it gathers companies of various sizes and sectors willing to pursue consistent climate goals related to neutrality.
Its first objective is to imagine the best possible framework and methodology for defining and encouraging corporate carbon neutrality, along with corporate partners and an independent scientific council.
http://www.netzero-initiative.com/en  About ENGIE

About Stonewater
Stonewater is a social housing provider, with a mission to deliver good quality, affordable homes to people who need them most. We manage around 32,500 homes in England for over 70,000 customers, including affordable properties for general rent, shared ownership and sale, alongside specialist accommodation such as retirement and supported living schemes for older and vulnerable people, domestic abuse refuges, a dedicated LGBTQ+ Safe Space, and young people’s foyers.
https://www.stonewater.org

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Retrofitting to net-zero