Written evidence submitted by the Mineral Wool Insulation Manufacturers Association (MIMA)



  1. MIMA is a trade body providing an authoritative source of independent information and advice on non-combustible glass and stone wool insulation. We represent leading mineral wool insulation companies in the UK, promoting the benefits of mineral wool insulation and the contribution it makes to the energy efficiency of buildings and the comfort, health and safety of their occupants.


  1. MIMA is grateful for the opportunity to respond to the EAC’s call for evidence on Sustainability in the Built Environment. This is an important area of focus, and addressing embodied emissions in buildings will be critical for achieving national climate change mitigation objectives. Our response highlights a number of areas we believe Government policies on embodied carbon should address in the coming years.

Question 1 - To what extent have the Climate Change Committee’s recommendations on decarbonising the structural fabric of new homes been met?

  1. The EAC will be aware of the Climate Change Committee’s (CCC) recent assessment of the potential for emissions reductions through changing construction practices in their 2019 report UK Housing Fit for the Future.[1]


  1. MIMA agrees with the principle in the CCC’s letter to MHCLG on 18 February 2020 which recommends that the “Future Homes Standard must also set a framework for assessing the significant emissions in building materials…”[2] Our response sets out in more detail key considerations for such a future framework.

Question 2 - How can materials be employed to reduce the carbon impact of new buildings, including efficient heating and cooling, and which materials are most effective at reducing embodied carbon?

  1. MIMA is supportive of a gradual introduction of a national mandatory framework to reduce embodied carbon in new buildings. We agree with the UKGBC that it is very important for climate change mitigation objectives that builders begin to routinely assess the embodied carbon of the buildings they construct, and over time disclose and seek to reduce the embodied carbon to a suitable baseline level for the type of building in question.


  1. It will also be essential to avoid potential unintended consequences of introducing requirements in this area. We cover a number of important prerequisites in our response to Question 5 and below we make four high-level points which we believe should be factored into future frameworks.

Combined operational and embodied carbon impacts

  1. Embodied emissions resulting from the extraction, manufacture and assembly of materials plus maintenance and end-of-life disposal account for around 50% of the overall carbon footprint of new buildings, and hence reducing this embodied carbon will be a necessary part of the drive towards a net zero economy. MIMA fully supports this transition, though we recognise that insulation itself will represent only a small proportion of the embodied carbon of a building, compared to say the foundations, walls, floors and roofs.


  1. Mineral wool insulation has impressive environmental credentials, for example:






  1. And our members continue to strive for improvements. For example, one member has set a goal of reducing the embodied carbon of their products by 2025 by 15% compared to 2019. Another has set an ambitious science-based target to reduce their global corporate greenhouse gas emissions by a third by 2034, approved and verified by the Science Based Targets initiative.


  1. However, when creating policy in this area it is important for policymakers and the industry not to lose sight of the emissions created by using buildings: heating, cooling and powering them. Overall these emissions currently significantly outweigh those from embodied carbon, and although the balance will shift as the electricity grid decarbonises, at present there is still much work needed to reduce these “operational” emissions. Not least, ensuring that the carbon reductions required by building regulations are achieved in practice, and the energy and carbon “performance gap” is reduced.


  1. Therefore, future policies must not inadvertently disincentivise or rule out the use of categories of products which might have a higher upfront embodied carbon impact than other materials in absolute terms, but their purpose is to save significant amounts energy and carbon over their lifetime. For example, finished mineral wool products save far more energy in use than is expended in their manufacture. It is vital that the combined impact of operational and embodied carbon is accounted for.


  1. It should also be remembered that the benefits of grid decarbonisation can extend to manufacturing plants using electricity in their production processes, helping to reduce embodied carbon associated with manufacture.

Broader procurement considerations

  1. Expanding on the point above, we would also caution against a future framework that inadvertently reduces product choice for designers and procurers. Embodied carbon is calculated at a building level and therefore due consideration must be given to the role a product plays in ensuring buildings are able to meet their functional requirements rather than simply comparing products side by side. For example, mineral wool thermal insulation products also provide acoustic insulation so the use of additional layers for acoustic performance, which may be necessary if choosing another thermal insulation type, are not required.


  1. Procurers must be able to continue to choose building materials based on a range of necessary performance metrics including acoustic performance, ability to resist the spread of fire, how well the materials perform in reality in use, durability, the sustainability credentials of the system from “cradle to grave”, and the breathability and the fit-ability of the system. These broader measures of performance must not be de-prioritised.

Product durability

  1. Again, related to the point above, the durability and lifespan of products should also be accounted for. Insulation is a “fit and forget” measure sometimes lasting for the life of the building. If an insulation product has a similar upfront embodied carbon impact to another type of product, but that product needs to be replaced three or four times over the life of the building, then the insulation would have a significantly lower overall impact.


  1. Similarly, if the balance of operational carbon performance vs embodied carbon is to be accounted for, then the durability of the materials themselves is also important. The in-use thermal performance of the insulation, for example, must continue for its lifespan, and not degrade over time.


Timing the introduction of requirements

  1. Lastly, we recognise the need for requirements in this area to be introduced sooner rather than later, and we support a trajectory which sees reduction targets potentially being introduced from 2025, with assessment and disclosure starting sooner provided the issues we raise in Question 5 are addressed.


  1. However, it is also important that policymakers understand the timetables involved when businesses undertake decarbonisation improvements. For a factory to invest in replacing a furnace in order to reduce the carbon emissions of their products, or innovate to significantly increase the recycled content of its products, a minimum amount of lead-in time will be required to make such changes. The policy environment should support such structural changes, for example through innovation funding, and give businesses long-term certainty about the requirements their products will be expected to meet.

Question 3 - What role can nature-based materials can play in achieving the Government’s net zero ambition?

  1. Creating a net zero economy in the UK is an exciting prospect, but the scale of the challenge must not be underestimated.


  1. MIMA believes that every sector will need to play its part, and every resource called upon to meet the challenge. Manufacturers of building materials of all types will need to look at their performance and consider how it can be improved. Similarly, Modern Methods of Construction and timber building systems will be part of the solution, as will innovation in what might be considered “traditional” construction techniques. There is no single solution, and a well-functioning market needs to offer choice and meet consumer preferences as well as delivering against wider environmental, economic and societal goals.


  1. Additionally, as stated in Question 2, building products are chosen for a range of reasons including their sustainability credentials, thermal performance, performance in use, ability to attenuate noise, ability to reduce the spread of fire, contribution to good indoor air quality, breathability, and their cost-effectiveness etc. Singling out any type of building materials based on any one performance metric is inadvisable, in our view.


  1. With these points in mind, MIMA would hope the EAC Committee and the Government, will continue to vocally support the energy efficiency and heat decarbonisation sectors as a whole, including the mineral wool industry, as essential to improving the energy performance of buildings at scale, reaching net zero emissions targets and delivering on a range of wider policy objectives such as on fuel poverty and fire safety.

Question 4 - What role can the planning system, permitted development and building regulations play in delivering a sustainable built environment? How can these policies incentivise developers to use low carbon materials and sustainable design?

  1. See our response to Questions 2 and 5.

Question 5 - What methods account for embodied carbon in buildings and how can this be consistently applied across the sector?

  1. Any future framework on embodied carbon will require a robust “accounting” methodology i.e. a way for designers and builders to understand the embodied carbon of the materials they plan to use, and what this adds up to for the whole building.


  1. Getting the requirements for this assessment phase right is the first critical step, and there are three points we would like to make on this theme:

Resolving data quality issues

  1. Assessments of embodied carbon rely on many assumptions about the performance of building materials and products. While there is guidance available, such as from RICS[5] and the GLA[6], information needed will also normally be project-specific, and at the product level.


  1. The product data produced by manufacturers and used for assessments must be accurate, consistent and reliable. However, significant gaps remain in the availability of data on the embodied carbon of specific products. Some companies have already put their products through rigorous, often complex tests, while others may have no information at all on the environmental performance of their products, or only poor-quality information.


  1. In addition, although there are standards available in this area[7], there is currently no requirement to use them. Hence, even where companies have collected data, this is unlikely to have been done in a consistent way and so products cannot be compared in a reliable way. Lastly, underlying data sets used in the assessment of product environmental performance are proprietary, meaning again the outputs can’t be compared side-by-side, and this too will need to be tackled.


  1. As a result, at present, it is unlikely that designers will have access to the good quality data they need to perform embodied carbon assessments on a routine basis. This issue must be fully addressed before an embodied carbon framework is officially introduced, something which the Government acknowledged in Parliament, but not yet resolved:
  2. To consider embodied carbon at a building-level would require a standardised method of calculation supported by a robust evidence base and underpinned by widely adopted product standards. There is currently no widely agreed standardised method for certifying the embodied carbon of building products, so it was not included the Future Homes Standard consultation[8].


  1. Encouragingly, the Government’s most recent consultation on the Future Homes Standard[9] stated: “Alongside our work on the Future Homes Standard, we will carry out wider work to consider the future of energy efficient and low carbon buildings, looking beyond the scope of Building Regulations. This will examine some of the broader and more fundamental questions around how we can ensure that all new buildings are designed and constructed to be fit for a zero carbon future, including those raised through the consultation process, such as the role of Modern Methods of Construction and low carbon materials, including timber, in delivering low carbon construction where these can be used safely.


  1. If the Government were to signal in 2021 that the Future Homes Standard and Future Buildings Standard planned for 2025 will include a requirement for embodied carbon assessments, and, after consultation with industry, what method should be used, this would provide the strong incentive needed for companies to test their products, certify the performance in a consistent way, and resolve data issues over a four-year timeframe.


  1. Data issues are beginning to be addressed through databases such the Inventory of Carbon and Energy[10] and the RICS Building Carbon Database[11], making use of Environment Product Declarations (EPDs). See below. However, policy and legislation must now support the scaling process.

Cradle to grave

  1. Any future framework used to compare the embodied carbon of building materials must be standardised, as stated, and should include every element of the building’s life cycle, from “cradle to grave”. This means every RIBA design stage. From extraction of raw materials, manufacture, transport, construction, maintenance through to the “end-of-life” and disposal, as shown in Figure 1 from LETI’s Embodied Carbon Primer.

Figure 1

  1. In particular, we are aware that when the embodied carbon performance of construction materials, including insulation, is assessed, the end-of-life stage is sometimes not included. And as shown in Figure 2 below, again from LETI’s Embodied Carbon Primer, this stage is significant in terms of emissions. If certain materials must be disposed of in a way that releases GHGs back into the atmosphere, for example, then it is critical that the accounting framework includes this and that builders are not encouraged to choose materials based solely on their “upfront” performance (up to the building completion stage). This upfront performance would not be a true reflection of the material’s “whole life carbon” performance. This point is especially important for products with life spans significantly shorter than the building itself.


  1. The Embodied Carbon Primer also notes that during LETI’s consultation, “There was strong consensus that to support embodied carbon calculations it would be beneficial to have a common UK methodology on the end of life (EOL) of construction materials.”





Figure 2

  1. It is therefore our strong recommendation that any future framework on embodied carbon must cover every lifecycle stage of the product/building, including processes before manufacture, and end-life-stages.

Environmental Product Declarations

  1. EPDs produced by manufacturers based on European Standard BS EN 15804 2012, are a tool already available to demonstrate the environmental performance of products (and sometimes services) in a quantified way.


  1. EPDs are produced using data from product Life Cycle Assessments (LCA). As the name suggests, a LCA calculates the environmental impact of a product over its entire lifecycle, i.e. taking the products “whole life” into account – from pre-manufacture, manufacture, transport, use, and disposal. This guarantees a full evaluation of all inputs and outputs, ensuring negative environmental impacts do not get shifted to other life cycle phases of the product, and thereby excluded.


  1. EPDs are often used for marketing purposes and internally for the improvement of product manufacturing. And they can of course be used by building designers as part of a whole building assessment of environmental performance.


  1. EPDs are therefore a readily available tool for use in embodied carbon assessments. However, at present they are not a legal requirement. Schemes such as BREEAM and LEED give credits for the use of products with EPDs and hence, companies supplying projects under assessment by such schemes may already have EPDs. Also, currently, in general, larger companies are more likely to have invested in producing EPDs, which can be expensive.


  1. In our view, making EPDs a requirement in the UK; a prerequisite for official whole-building embodied carbon assessments, would be a beneficial next step. And once a requirement exists and EPDs are produced at scale, quality issues should start to be ironed out and cost reductions gradually seen.

Question 6 - Should the embodied carbon impact of alternative building materials take into account the carbon cost of manufacture and delivery to site, enabling customers to assess the relative impact of imported versus domestically sourced materials?

  1. Yes. It is our strong recommendation that any future framework on embodied carbon must cover every lifecycle stage of a product, including processes before manufacture, and end-life-stages.

Question 10 - What can the Government do to incentivise more repair, maintenance and retrofit of existing buildings?

  1. The retrofitting of existing buildings remains one of the most significant and cost-effective routes to achieving large-scale carbon reductions. The Government has recognised this to some extent by committing to raise the energy performance of UK housing to a level equivalent to an Energy Performance Certificate rating of C by 2035. At present, it is estimated that around 19 million homes (around 70%) fall short of this this standard, and only a tiny proportion achieve the highest A rating. So there is much work to be done, even to reach this relatively basic level of performance.


  1. Whilst this commitment by the Government is very welcome, there is a major policy and funding gap, and as yet, no clear strategy in place for reaching it. Especially in light of the recent scrapping of the Green Homes Grant voucher scheme. Urgently addressing this gap will ensure we get on track for deep emissions reductions, providing long-term industry confidence, and boosting skills and supply chains to decarbonise all housing tenures.


  1. The Department for Business, Energy and Industrial Strategy’s (BEIS) forthcoming Heat and Buildings Strategy must serve as the blueprint for decarbonising buildings this decade. A comprehensive and ambitious plan is needed for the UK to meet climate targets, create hundreds of thousands of new jobs in supply chains across the country, reduce energy bills and provide a sustained economic boost that aids a green recover. This Strategy will be the essential vehicle for establishing the policies and regulatory framework needed to provide households, businesses and financial institutions the long-term confidence to invest in homes, skills and supply chains.


  1. We refer the Committee to the Energy Efficiency Infrastructure Group’s (EEIG) recent briefing[12], of which MIMA is a member, which sets out six key asks to Government for getting the energy performance of the built environment on track over this Parliament, with a view to making significant progress by 2030 and ultimately achieving a net zero built environment by 2050.

May 2021

[1] See UK housing: Fit for the future? - Climate Change Committee (theccc.org.uk)

[2] See Letter: Future Homes Standard and proposals for tightening Part L in 2020 - Climate Change Committee (theccc.org.uk)

[3] See Background to the Green Guide to Specification : BRE Group

[4] See https://b80d7a04-1c28-45e2-b904-e0715cface93.filesusr.com/ugd/252d09_869f0ce2dc8a4a65a1b87890609ede32.pdf

[5] See Whole Life Carbon Assessment for the Built Environment, 1st edition (rics.org)

[6] See Whole Life-Cycle Carbon Assessments guidance | GLA (london.gov.uk)

[7] The UK framework for appraising the environmental impacts of the built environment is provided by BS EN 15978: 2011: (Sustainability of construction works — Assessment of environmental performance of buildings — Calculation method)

[8] See https://researchbriefings.files.parliament.uk/documents/CBP-8830/CBP-8830.pdf

[9] See Title (publishing.service.gov.uk)

[10] See Embodied Carbon Footprint Database - Circular Ecology

[11] See RICS Building Carbon Database

[12] See eeig_heatbuildingsstrategy_thebenchmarksforsuccess_0521.pdf (theeeig.co.uk)