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1. Overview

The following guidance is produced to assist applicants submitting bids for funding under the Optimised Retrofit Programme (ORP). It has been developed to help inform the applicants about the type of retrofitting the programme aims to financially support.

ORP 3 is for the period of 2022-2025. The main theme of the programme is affordable warmth and decarbonisation achieved through the best path for each individual home. 

Registered Social Landlords and local authorities have previously received a funding award allocation from Welsh Government to deliver phased activity of the Optimised Retrofit Programme in 2022-2023 and 2023-2024. For this year’s funding round to be considered for awarding, Optimised Retrofit Programme officials will require submission of an application (proforma) that outlines the intended costs for the year 2024-2025. Please note that the funding allocation will continue to be generated on a formula approach of stock numbers that is based on figures sourced from the 2020 data census.

Recipient organisations will be required to complete the proforma and to conform to the outlined format of the proforma. Submitted proformas will be considered by Welsh Government and any areas of clarification will be raised with the recipient organisation. When the Welsh Government are content the proforma is completed and meets the requirements set out below, a grant offer letter outlining funding and grant terms and conditions will be sent to the recipient organisation.

Successful projects will be monitored and evaluated, with recipient organisations required to adopt an open book approach as a condition of accepting the funding. For example, requests for prime documents such as evidence of defrayment, updated actual to forecast models, and project outputs could be requested by Welsh Government throughout the length of the programme.

2. Strategic context

In 2019, The Better Homes, Better Wales, Better World report was commissioned by Welsh Ministers to examine how homes in Wales could be decarbonised. The recommendations were accepted by Ministers including a commitment to pursue a residential decarbonisation programme. 

In response to the recommendations, it was agreed that an ‘Optimised Retrofitting’ approach would be adopted here in Wales. 

From this commitment and approach the Optimised Retrofit Programme (ORP) was established in 2020. Over the past three years a range of projects across the social housing sector have been supported and c £190m of funding invested. The ORP 3 Year 3 phase of funding seeks to continue to build on this to ensure that all social landlords in Wales engage with ORP.

In taking forward the decarbonisation of existing homes, we acknowledge that retrofitting existing homes is a complex and iterative process. Homes are likely to need to go through several stages of retrofit work to reduce their carbon incrementally, embracing innovation and experimentation over time. 

It has always been our intent that ORP takes a staged approach, using the social housing sector, and investment in it, to lead and inform retrofit for other tenures of homes. ORP is intended to act as proof of concept for approaches to both fabric and technology retrofit and establish a firm evidence base on which to develop our longer term retrofit strategy. 

Our focus for ORP 3 will continue to be optimising the thermal and energy efficiency of Welsh social homes. In deploying the programme, we ask landlords to optimise insulation, maximise air tightness, and carefully consider ventilation to reduce heat loss and make homes ‘fabric ready’. This approach balances the cost of making homes ‘fabric ready’ against the provision of technological measures to make homes cheaper to run and reduce carbon emission. 

Key to the programme is:

  • Deliver the programme in ways that align the design and delivery of affordable housing with the seven goals of the Well-being of Future Generations (Wales) Act (WFGA) – Well-being of Future Generations (Wales) Act 2015 – The Future Generations Commissioner for Wales.
  • Encourage landlords to develop a strategic approach which aligns with the targets and approach set out in Part 3 of Welsh Housing Quality Standard 2023 when considering measures to improve affordable warmth and decarbonisation of homes.
  • Demonstrate benefits associated with new ways of retrofitting, with a view to encouraging wider uptake.
  • Harness opportunities to deliver jobs, skills training, and develop local industry, embracing foundation economy principles and supporting wider regeneration.
  • Contribute to Welsh Government policy objectives around reduction in waste and circular economy.
  • Support public involvement by disseminating key findings and maximise learning.

Additional resources

Further details regarding ORP and contextual information on wider developments can be found on the Welsh Government website or via the following links:

Optimised RetroFit Programme | GOV.WALES

Welsh Housing Quality Standard 2023 GOV.WALES

Net zero skills Wales | GOV.WALES

Climate change GOV.WALES 

Supporting businesses in Wales | Business Wales (

Procurement & Tendering for work 


Net Zero Carbon Hwb

Please submit all Case Studies to: 

Case study (housing) form - Carbon Hwb (

Case study (other) form - Carbon Hwb (

Welsh Retrofit contractor dashboard

This dashboard lists contractors working under various procurement frameworks in Wales. Please note this list does not constitute a Welsh Government recommendation, and users of this dashboard should conduct their own due diligence on the companies listed.

3. Timescales

Main dates for ORP 3 Year 3 2024 to 2025 

April 2024

Guidance and Submission Documents issued 

Submission documentsTo be returned 16 May 2024
Grant awardedBy 16 June 2024 (dependent on successful submission)
Funding claimedBy 31 March 2025

4. Objectives of Optimised Retrofit Programme

The objectives of Optimised Retrofit Programme are as follows:

  1. To support social landlords to develop a strategy to align with the ‘Affordable Warmth and Decarbonisation’, elements of Welsh Housing Quality Standard 2023 
  2. To support social landlords to approach the decarbonisation of homes enabling underpinning factors to be addressed such as skills, procurement, finance models and material selections
  3. To support social landlords to innovate in their approach to measure in the decarbonising of their housing stock homes, adopting a risk appetite which matches the innovative and entrepreneurial activity required to decarbonise effectively and efficiently.
  4. To support the development of appropriate approaches to decarbonising the private rented and owner occupier sectors.

5. Requirements of Optimised Retrofit Programme year 3

  1. Social Landlords are required to undertake retrofit measures to homes using PAS 2035 (PAS 2035:2023 Specification for the energy retrofit of domestic buildings).
    Lodgement of works on the TrustMark Data Warehouse is mandated (please note the ORP and landlord drop down lodgement menu on TrustMark Data Warehouse) 

    PAS 2035:2019 / PAS 2035/2030:2023 • TrustMark (We are now in a transition period whereby the 2019 standards will be withdrawn on 30th March 2025 and replaced with the new 2023 standards. )
  2. Social landlords are required to install Environmental & Energy Monitoring Sensors compliant with, ‘Optimised RetroFit Programme: environmental and energy monitoring’. 

    Landlords are required to include in their applications installation Environmental & Energy Sensors only to homes that will inform future retrofit programmes (such ORP 3 2024/25) to create pre-retrofit data to support choice of measures for homes.

    The landlord is responsible for informing the sensor supplier to send the data to the ORP dashboard (that TrustMark has established) that ORP landlords have access to.
  3. Social landlords are required to use existing information and focussed survey data to develop a Whole Stock Assessment for their homes. 

    Social landlords should produce a Target Energy Pathway for each home undertaking retrofit measures in ORP, setting out how that home will ultimately achieve targeted levels of affordable warmth and decarbonisation.

    Guidance has been issued with WHQS ’23 on how landlords should approach a ‘Whole Stock Assessment and Target Energy Pathways’
  4. Social landlords are required to report on number of premises receiving retrofit measures, type of intervention used and other key outputs. 
  5. Landlords are required to produce a case study for each project.
  6. Social landlords are required to provide details as to who their product and services suppliers are e.g. name, web page, business address, product / service procured, method of procurement, how you found the supplier). 
  7. Social landlords are required to supply details and comments on the training their staff and suppliers are accessing in Wales as part of Welsh Govt ongoing training support review Optimised RetroFit Programme: training | GOV.WALES
  8. Social landlords are required to report on additional funding streams that are applied for that relate to retrofit activities which includes own contribution and other financial streams e.g. those linked to Lodgement as well as other financial services / funding schemes with other partners. 

    The objective is to develop the financial and insurance services sector linked to retrofit of homes and the associated supply chain of products and services.

6. Eligibility

  1. Payments will be released in arrears based on activity completed as part of your programme. This will be based on a quarterly payment cycle throughout the 2024/2025 financial year, with a requirement that all works are completed no later than 31/03/2025. This includes ongoing works undertaken as part of historic iterations of the programme. Any works outstanding after this point are not eligible for grant funding.
  2. Welsh Government reserve the right to amend scheme acceptability dates and requirements. These will be discussed directly with successful scheme applicants at an appropriate time.
  3. To support social landlords to fund works that are in addition to their current ‘Repair, Maintain and Improve’ (RMI) programmes, and includes not bringing forward from RMI, future years to use with the ORP grant. Typically, these programmes are currently aligned around existing Welsh Housing Quality Standard (WHQS) 2008 standard.
  4. Eligible capital costs are costs that can be directly linked to the programme such as insulation, heat pumps and other interventions. Eligible revenue costs are costs that can also be directly linked to the programme such as direct labour cost.
  5. Up to 10% of the total grant allocated funding threshold can be used for the following non-direct activities:

    - innovation and research linked to the decarbonisation of your housing stock.
    - In house programme management fees
    - Third party management fees (considered on a case-by-case basis)
    - Procurement of in-house asset management and stock modelling software.
  6. An analysis of estimates for cost of ‘External Wall Insulation’ for ORP3 Yr 2 was carried out on 23 schemes submitted by social landlords;

    - For houses, excluding the highest / lowest cases the average submission is £179m2, and £19,600 per house.

    - For flats, the large variation in external wall area makes a cost / m2 rate highly variable. The average cost per flat is £15,000 per flat.

    Landlords are expected to state the costs of EWI and IWI for flats and houses in the ‘Eligible costs and Scheme Details Sheet’ (see Scheme Tabs - Cell D5)

    Further justification will be required if your costs materially exceed these baseline costs.
  7. Environmental & Energy monitoring systems and survey fees are eligible costs.
  8. VAT (Value Added Tax) applied on expenditure incurred will only be considered as eligible expenditure if you are unable to recover the VAT within your own taxation rules.

7. Evaluation

Welsh Government intends to build an evidence base of what works and what doesn’t, to inform future policy and investment decisions. As part of the evaluation, case studies are to be published on the Net Zero Carbon Hwb .

Evaluation requirements will be confirmed in the Grant Offer Letter awarded for successful projects.

All successful projects will be required to participate in evaluation exercises as a condition of grant. Specific additional evaluation may be commissioned to investigate an individual scheme’s innovation focus, and the nature of this evaluation will be discussed and agreed on a scheme specific basis. Timely provision of data is also a condition of the funding.

After initial analysis the data collected will be publicly available, to note this will be published on the ORP webpage and will be anonymised. We may also require and support the development of case studies.

8. Application process

8.1 Submitting applications 

All correspondence and your completed application submission should be sent electronically to: The relevant Welsh Government ORP lead may also be cc’d within your communication: 

8.2 Compliance assessment

Applicants should note the following:

  • A fully completed application form, eligible costs and scheme details sheet, and any necessary attachments must be submitted. 
  • Applicants have committed to meet all criteria set out on the application form. 
  • Applicants have committed to participate in the monitoring and evaluation of funded projects. 
  • Applications must have regard for UK Subsidy Control Statutory Guidance. This will be verified by Welsh Government. 
  • Welsh Government will request further details, additional information or/and clarification questions as necessary to assess and approve the ORP application forms and applicants are expected to respond to these requests in a prompt fashion.

9. Assessment process

The proposals will be assessed against how they align with the general aims and objectives of the optimised retrofit approach and the requirements set out above.

Applicants may be asked to provide additional information or/and clarify submissions as outlined above. Applicants will be notified by Welsh Government officials of successful proposals and/or caveated proposals prior to grant offer and award.

9.1 ORP grant offer

A grant letter will be made following the successful completion of all the checks and processes referred to above. A proposed payment profile must be submitted with the submission.

10. Communications and branding

Acknowledgement of Welsh Government support should be displayed on all publicity, press releases and marketing material produced in relation to the project, as well as on site during development. This includes site hoardings.

Such acknowledgement must be in a format approved by Welsh Government and must comply with the Welsh Government’s branding guidelines.

11. Further information

If you would like further advice or information about the ORP, please email