Before retrofit work or grant funding can proceed, you need an independent PAS 2035 retrofit assessor. Here is what to look for and why independence matters.
Whether you are a homeowner looking to access ECO4 funding, a landlord preparing for the 2030 EPC C requirement, or an installer needing a compliant assessment before work can begin, you will need a qualified and independent PAS 2035 Retrofit Assessor. This guide explains what to look for, why independence matters, and what to expect from the process.
PAS 2035 is the UK standard for domestic retrofit. To carry out a compliant Retrofit Assessment, an assessor must hold a recognised qualification in retrofit assessment and be registered with an accreditation scheme. In the UK, accreditation schemes include ABBE, Elmhurst Energy, and others approved by the relevant industry bodies.
ABBE (the Awarding Body of the Built Environment) is an Ofqual-regulated awarding body that certifies Retrofit Assessors through its Level 4 qualification route. An ABBE-accredited Retrofit Assessor has demonstrated the knowledge and competence required to carry out a full PAS 2035-compliant assessment.
TrustMark registration is a further indicator of quality. TrustMark is a government-endorsed quality scheme covering energy efficiency and retrofit work. Firms registered with TrustMark have met additional standards for customer care, technical competence, and trading practices.
One of the key requirements of PAS 2035 is that the Retrofit Assessor must be independent from the installer carrying out the work. This is not a formality: it is a safeguard that ensures the assessment is objective and the Improvement Measures Report reflects what the property actually needs, rather than what a particular installer wants to sell.
If an installer offers to arrange the assessment themselves and carry out the work, it is worth checking that the assessor they use has no commercial relationship with the installer. A homeowner or landlord commissioning their own independent assessment before approaching installers is in a stronger position to compare quotes and ensure the recommended measures are genuinely suitable.
A full Retrofit Assessment typically takes one to two hours on site, depending on property size. The assessor will examine the property's fabric (walls, roof, floors, windows), heating systems, ventilation, and moisture levels. They will also review any existing EPC and survey data.
Following the visit, you will receive an Improvement Measures Report. This sets out the current energy performance of the property, the most effective improvement measures in priority order, and an indication of grant eligibility. The report is the document that ECO4 managing agents and installers use to design the funded works.
South London's housing stock has particular characteristics that a local assessor will understand well. Victorian and Edwardian terraces with solid walls, basement flats, converted maisonettes, and mansion blocks all present different challenges for retrofit. Conservation area designations across large parts of Lambeth, Wandsworth, and Southwark affect which external measures can be installed. A local assessor will be familiar with these constraints and factor them into the report.
Carn Energy is an ABBE-accredited, TrustMark-registered retrofit assessor based in SE21, covering all of Lambeth, Wandsworth, and Southwark. We carry out independent PAS 2035 Retrofit Assessments for homeowners, landlords, and ECO4 managing agents. We have no commercial relationship with any insulation or heating installer, so our reports reflect what your property genuinely needs.
To book a Retrofit Assessment or to discuss whether your property qualifies for grant funding, visit our Retrofit Assessment page, read more about our qualifications on the About page, or get in touch directly.
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