This CPD, sponsored by Kingspan Insulation, looks at the role of PAS 2035 and PAS 2030:2019 in the new Retrofit Standards Framework, how these have been developed, and the framework’s requirements for the construction industry
The UK’s housing stock is among the oldest and least energy-efficient in Europe, with more than half of properties having been built before the 1965 Building Regulations introduced the first requirements for thermal insulation. Estimates suggest that energy use from domestic properties accounts for around 14% of total UK greenhouse gas emissions and that in order to meet the government’s UK statutory net-zero emissions target by 2050 (2045 in Scotland), it will be necessary to shrink average household heating emissions by 95% (from 2,745kg CO2e to just 138kg CO2e).
As well as significantly tightening the energy performance requirements for new homes, achieving this target will require a retrofit programme on an unprecedented scale, affecting virtually all domestic buildings in the country. These refurbishment projects present a diverse range of challenges for contractors, with factors including the size, construction type, age, orientation and location of the property impacting the most suitable energy efficiency measures (EEMs) and the scale of savings that can realistically be achieved.
In order to establish and uphold best practice in energy efficiency retrofit work, the government has introduced a Retrofit Standards Framework that seeks to avoid piecemeal implementation of EEMs by requiring the characteristics of each property to be carefully assessed, and a medium-term action plan created, before any measures are introduced.
Central to this framework is PAS 2035, which clearly identifies the process of assessing a property, how EEMs should be chosen in response and outlines how long-term monitoring can be carried out. It also clarifies the responsibilities and qualifications for individuals involved in the retrofit process. This specification dovetails with an updated version of PAS 2030, which now solely focuses on the installation, commissioning and handover of EEMs. This CPD looks at how the new framework has been developed and the requirements for the construction industry.
Each Home Counts review
In 2015, the government commissioned an independent review, chaired by Peter Bonfield, the then-chief executive of BRE, to examine the retrofit energy efficiency and renewable energy marketplace and to make recommendations on how to raise consumer confidence in these measures. This followed mounting concerns over the quality of existing practice within the industry and the need to close the “performance gap” between the expected energy performance and actual energy performance of homes following the installation of EEMs.
The final report, also known as the Bonfield review, was published in December 2016. It made 27 key recommendations, proposing a new approach to retrofit work underpinned by establishing a quality mark, codes of conduct and practice, and an overarching framework for end-to-end delivery of retrofit energy efficiency and renewable energy measures.
Since its publication, the government has worked with an implementation board to enact these recommendations. The quality mark has been established by extending the remit of the government’s existing TrustMark scheme to include the repair, maintenance and improvement, retrofits and energy efficiency sectors. It is expected that future government-supported retrofit schemes, including a revised version of the Energy Company Obligation (ECO), will require work to be completed by TrustMark-registered businesses.
To become a registered business, companies must undergo assessment by a suitably qualified certification body. Previously, workers had to be assessed to the installation specification PAS 2030:2017 under the instruction specification PAS 2031:2017. Last June, however, the government introduced three new specifications:
- PAS 2030:2019 – Specification for the installation of energy efficiency measures in existing dwellings and insulation in residential park homes
- PAS 2031:2019 – Certification of energy efficiency measure installation in existing buildings and insulation in residential park homes
- PAS 2035:2019 – Retrofitting dwellings for improved energy efficiency. Specification and guidance.
Together, these documents form key parts of the framework for energy efficiency retrofits on domestic buildings. From 30 June 2021, it will become compulsory for all certification bodies and registered businesses under the TrustMark scheme to comply with, and to be able to evidence compliance with, the relevant specifications. Therefore, it is important that companies work to familiarise themselves with the new requirements.
PAS 2035 – A whole-house approach
PAS 2035:2019 is the overarching document in the Retrofit Standards Framework. It covers all aspects of assessment, EEM package design and monitoring. Consequently, the revised version of PAS 2030 has been streamlined and several sections of the 2017 version, including guidance about the scope and content of designs for EEMs, the interactions between EEMs and assessment of existing ventilation systems, have been removed and moved into PAS 2035.
At the core of PAS 2035 is a commitment to the “whole-house approach”. This means all aspects of the property need to be carefully evaluated before any EEMs are implemented. This approach recognises there are no one-size-fits-all solutions and that it is not only impractical to expect all buildings to reach the same level of performance, but that attempting to do so may actually harm some older buildings, creating unhealthy internal environments and damaging some architectural heritage.
PAS 2035 clearly outlines the processes for a risk assessment and whole-dwelling assessment, which takes into consideration of how aspects such as a building’s construction, architectural character and patterns of use, may constrain retrofit work. It emphasises that protecting occupant health, wellbeing and comfort should be prioritised above improving the energy efficiency of the property.
A medium-term (20–30-year) plan should be created. This should:
- Identify an appropriate target improvement level within these constraints and the set of EEMs which should be deployed.
- Highlight potential interactions between these EEMs to avoid unintended consequences such as thermal bridging.
- Set out a clear order in which EEMs should be fitted considering how the installation of certain measures may make it more difficult or impossible to install others at a later date.
- Be created in a format which can be updated as work progresses or new knowledge or materials become available.
PAS 2035 emphasises that a “fabric first” approach will provide a technically sound and cost-effective improvement method and should always be considered as part of the planning process. This requires the building to first be raised to a good state of repair, addressing issues such as poor pointing, cracked brick and water ingress or damp. Next, low-cost measures can be implemented such as fitting low-energy lighting and improved heating controls. Steps can then be identified to improve the actual fabric performance of the building envelope by installing insulation, reducing thermal bridges and air leakage, alongside achieving adequate heating and ventilation.
The specification points out: “It makes sense to ensure that the existing building fabric is as efficient as possible before spending resources on other measures. Subsequently, because insulation measures are generally among the most cost-effective and long-lasting, and thus best investment, insulation is usually the most appropriate next step. Insulating the fabric first also reduces the required capacity and cost of the heating system.”
The scope of this work is defined by the constraints highlighted in the initial building assessment. For example, the use of solid wall insulation may not be possible on listed buildings or those within conservation areas. Similarly, a risk-based approach is recommended when selecting EEMs for older properties and care needs to be taken to ensure adequate ventilation in all properties when the thermal performance and airtightness of the envelope is improved.
One of the key concerns raised within the Each Home Counts review was that EEMs, and particularly fabric-first measures, were often let down by poor detailing at the design stage and during the installation. In response, PAS 2035 highlights the need to “concentrate on the interfaces”, ensuring that close attention is paid to all junctions within a property to ensure that insulation layers and air barriers are continuous and potential thermal bridges addressed.
Measures can then be identified to meet the remaining heat and energy demand as efficiently as possible, including the use of renewable technologies. To support best practice, PAS 2035 also provides guidance on how properties can be monitored and evaluated (where appropriate) and how learning can be fed back into the industry to support work on other properties.
Beyond the design and specification of measures, PAS 2035 looks to place the voice of occupants at the heart of the refurbishment process. In addition to supporting consumer confidence, this recognises that the way occupants use buildings can undermine the performance of EEMs and contribute to the performance gap between the designed and actual performance of the building. A typical example of this is occupants in highly insulated and airtight buildings opening windows while running heating systems.
To ensure occupants and clients (when they are not the same) are well informed, PAS 2035 requires occupants to be fully advised of the improvement plan for their property (including how the measures work and why they have been scheduled in a particular order) and how they should maintain it after work is complete to maximise its energy efficiency.
An online data warehouse is being developed to support the Retrofit Standards Framework. This will allow members of the retrofit process to log work in a single location, accessible to other members to ensure work is integrated. A property hub is also being created to allow homeowners to view relevant information from the data warehouse.
Roles and responsibilities
Several key positions have been created within the Retrofit Standards Framework. To ensure competency within these positions, PAS 2030 and PAS 2035 set out clear vocational or professional qualification requirements that must be met. In practice, multiple roles within this process can be fulfilled by the same individual, providing they are sufficiently qualified and any potential conflicts of interest are highlighted.
The primary role is the retrofit co-ordinator, who is responsible for providing end-to-end project oversight (including for any monitoring work). The retrofit co-ordinator commissions the design of the measures, contracts the installer and acts as the homeowner’s advocate for any issues. The co‑ordinator can be employed by the client or any other party involved, but is ultimately responsible for protecting the client and public’s interest and ensuring processes comply with PAS 2035.
To assist this work, PAS 2030 and PAS 2035 outline a clear, staged process through which all retrofit projects should proceed:
1. A retrofit adviser discusses options for reducing energy consumption with the householder, both through improvements to the property and changes in occupant behaviour.
2. If the householder opts to further explore improvement opportunities, the retrofit co‑ordinator must conduct a risk assessment using information including existing Energy Performance Certificates, surveys, interviews with occupants/owners and observations during site visits. This data will be used to grade the property risk from A (lowest) to C (highest) and will determine which path the project follows during subsequent stages. The risk assessment must be repeated and updated as new measures are implemented.
3. A whole-dwelling assessment is undertaken by a retrofit assessor. This assessment includes:
- A comprehensive appraisal of the dwelling’s heritage, construction, any installed services and existing defects
- Identification of any planning constraints
- An appraisal of the building envelope dimensions, U-values, moisture properties and suitability for improvement.
For projects on risk paths B or C, additional assessments must be undertaken. These may include:
- An appraisal of occupants and any special requirements they may have
- Assessment of existing ventilation
- Estimate of annual fuel use and emissions
- Assessment of air permeability
- Assessment of the significance of the building using the guidance in BS 7913:2013 – Guide to the conservation of historic buildings.
4. A retrofit designer uses the outputs from the whole-dwelling assessment to design a package of suitable EEMs. The designer is expected to pay particularly close attention to construction details for any fabric EEMs and how measures that do not physically connect may interact – for example, considering how changes to the insulation level will impact the capacity requirements for new heating systems. For projects on risk paths B or C, the retrofit co‑ordinator must carry out an improvement option evaluation prior to the retrofit design to calculate the payback period and carbon cost-effectiveness of the improvement options.
5. The retrofit co‑ordinator creates a medium-term improvement plan for the next 20 to 30 years, creating a sequence for implementing the EEMs to maximise long-term benefits for the owner. This sequencing will also be designed to prevent one measure negatively impacting another or preventing the implementation of future measures.
6. The co‑ordinator communicates the improvement plan to the client, outlining any statutory approvals that may be required and obtain their approval for any work. They will then provide retrofit installers with briefings to explain the design intent, sequencing and provide advice on any new technologies.
7. Installation of the EEMs is carried out by the retrofit installers in accordance with PAS 2030. It is the installers’ responsibility to demonstrate these processes comply with PAS 2030 and to provide evidence of this to the retrofit co-ordinator.
8. The retrofit installer will also oversee any testing and commissioning of EEMs. The requirements for both these stages should be contained within the retrofit design and be carried out in accordance with PAS 2030.
9. The retrofit co-ordinator will arrange to ensure handover is completed with the occupant and owner of the property. This includes a physical inspection of the measures and clear information about safe operation, care and maintenance. The co-ordinator will retain any testing certificates, commissioning records and other manuals and paperwork, making copies available to the client. They will also recommend that a new EPC is prepared and, if accepted, undertake this work.
10. PAS 2035 also requires that retrofit projects are subject to evaluation and potentially monitoring to confirm if the expected outcomes have been achieved and to feed lessons back to all parts of the supply chain, including the building owner and occupants. This work is carried out by a retrofit evaluator.
11. Initially, the retrofit evaluator carries out a basic evaluation within three months of handover. This includes a measure-specific questionnaire for homeowners, confirming if the expected outcomes have been achieved and allowing them to raise any points of dissatisfaction or highlight unintended consequences of the work. If the homeowner, evaluator or co-ordinator feels the outcomes are significantly different than expected then two further levels of evaluation and monitoring can be carried out: intermediate and advanced. These include a variety of assessments such as airtightness tests, fuel use metering and thermographic surveys, and must be completed with six months of handover for the intermediate and two years of handover for the advanced. The retrofit evaluator makes recommendations for any remedial actions and circulates these to all other parties within the retrofit process.
TrustMark-registered business deadline
As mentioned earlier, a transitional period has been set to give firms the chance to get up to standard and be certified. This period ends on the 30 June 2021, meaning that all firms wishing to trade under the TrustMark scheme must be certified to PAS 2030 and compliant with the requirements within PAS 2035 by this point.
In addition, as the Retrofit Standards Framework moves key responsibilities out of the scope of PAS 2030:2019, registered businesses must also be able to evidence compliance with PAS 2035, once certified to this level.
Seeing the full picture
There is little question that the process of upgrading existing homes to improved energy efficiency standards is among the most difficult in the construction industry.
The Retrofit Standards Framework, underpinned by PAS 2035 and PAS 2030:2019, provides a clear and methodical approach for this work, helping to ensure that all improvements are carefully considered in relation to the characteristics of each project and that best practice knowledge is passed on through the industry. By embracing this approach, industry professionals can ensure they are prepared for the challenges of delivering retrofits that perform as expected and deliver long-term value for homeowners.