This digest aims to provide small and medium-sized enterprises (SMEs) and micro-construction businesses with valuable insights into retrofit practices and the benefits of getting involved. Discover what retrofit means, why it’s essential, and how it can enhance your business operations.
What is Retrofit?
Retrofit is the process of improving the performance of an existing building by installing additional measures that weren’t included in its initial design. A high proportion of the UK’s current housing stock does not meet the level of energy efficiency and sustainability required for the UK to achieve its Net Zero targets by 2050.
Energy used in domestic buildings accounts for around 26% of the UK’s total emissions. Therefore, retrofit is a significant priority for decarbonisation.
Why Retrofit Matters to Small & Micro Construction Businesses
The scale of the opportunity
- Twenty-nine million UK homes require energy upgrades by 2050 – that’s around 1.8 homes every minute.
- Heating and powering homes accounts for roughly 26 % of UK carbon emissions.
- Government and local‑authority programmes are injecting billions of pounds into domestic retrofit, prioritising SMEs in local supply chains.
Why get involved?
- Diversify your revenue stream – retrofit projects range from simple insulation jobs to whole-house refits.
- Build customer loyalty – homeowners are increasingly seeking proven energy-saving solutions.
- Future-proof your business against tightening building regulations and net-zero procurement criteria.
Benefits delivered to households
- Lower energy bills and protection from price shocks.
- Healthier indoor environments – reduced damp, mould and respiratory illness.
- Increased property value.
Standards & Compliance – What You Must Know
| Standard / Scheme | What it Covers | Why it Matters |
| PAS 2035 (Whole‑House Retrofit) | Assessment, design, coordination & evaluation framework | Mandatory for funded domestic retrofit projects from 30 June 2021. Defines the professional roles. |
| PAS 2030 (Installation) | Quality requirements for installing energy‑efficiency measures | You need certification to access ECO, SHDF and other schemes. |
| TrustMark | Government‑endorsed quality mark | Required gateway to public funding and gives consumer assurance. |
| Building Regs Part L | Conservation of fuel & power in new‑build and existing homes | Proof of photographic evidence now compulsory on site. |
| BS 7913 / BS 5250 | Conservation of historic buildings / Moisture management | Essential when working on traditional or heritage properties. |
Fabric‑First principle – insulate and make airtight before adding low-carbon tech; lowers running costs and allows smaller heating systems.
The PAS 2035 Roles
Retrofit Advisor, Assessor, Coordinator, Designer, Installer and Evaluator. SMEs can cover multiple roles if the competency requirements are met.
Pathway to Becoming a Trusted, Accredited Installer
- Upskill & Train
- Take Retrofit Academy Level 3–5 courses or equivalent NVQs.
- Encourage multi-skilling (insulation, airtightness, low‑carbon heating).
- Implement a Quality Management System (QMS)
- Document processes, H&S, customer care and complaints handling.
- Align with PAS 2030 clauses.
- Achieve Certification
- Engage a UKAS-accredited body (e.g. BBA, Blue Flame, Certass, NAPIT).
- Pass technical inspection on at least one live install.
- Register with TrustMark – enables you to work under ECO4, SHDF, HUG, etc.
- Consider Licence Plus for fabric‑first, whole‑house credentials and marketing edge.
- Maintain Competence & CPD – keep staff cards, refresher training and site audits up to date.
Typical SME Resource Commitment
- Time to certification: 3‑6 months (including training & audit).
- Direct costs: £4,000 – £7,000 (training, audit, TrustMark fees).
- Indirect costs: allocate 1 day / week for QMS admin in the first year.
Ten-Step Action Plan for SME and Micro-Businesses:
- Read the PAS 2035 & PAS 2030 standards – free via the BSI library for SMEs.
- Map your current competencies against required roles.
- Select a training provider (e.g. Retrofit Academy) and book courses.
- Build a simple QMS – document, review and improve monthly.
- Choose a certification body and schedule your audit.
- Register with TrustMark and create an online profile.
- Pilot a low-risk project with insulation or ventilation measures; gather photographic evidence for Part L compliance.
- Explore local authority pipelines – attend ‘Meet‑the Buyer’ events for ECO4, SHDF, and HUG.
- Promote your new credentials – add TrustMark and Licence Plus logos to vans, quotes, and social media.
- Monitor outcomes & collect data – use smart meters and customer feedback to demonstrate quality and drive referrals.
Further Resources
- The Retrofit Academy CIC – courses, CPD and community.
- BSI Retrofit Standards Framework – Infographic and Standard Suite.
- TrustMark’s ‘Five Steps to a Retrofit Project’ video.
- Ofgem ECO4 delivery guidance.
- NHIC Doorstep Digest archive – examples of clear, homeowner-friendly language.
This digest is a condensed version of An Introduction to the Retrofit Sector (2023) produced by the Retrofit Academy for the Innovation Driven Procurement Project, funded by the CITB. A full copy of this guide can be found here:
https://www.theidp.co.uk/_files/ugd/f23d42_6d5072b91ab848388d0789c63353948c.pdf
The NHIC would like to thank the RMI WG2 Consumer Voice members for their contributions to this guide.
Please note that this guidance document, produced by the NHIC, was accurate at the time of its creation. However, information and regulations may have changed since this document was published. Therefore, seeking the most up-to-date information and expert advice is always advisable before making any decisions related to improving your home.
