Energy Assessments for Retrofit Projects

Energy Assessments for Retrofit Projects

Retrofit means improving an existing building: insulation, new windows, a heat pump, solar PV, better ventilation and controls. Whether it is a single flat, a block or an office, every retrofit project needs the same things from the energy side: a clear starting point, proof of what the upgrades achieve, and test results that building control and funders accept. That is our part. We are energy assessors with more than 17 years of experience and more than 8,500 assessments, and we work with landlords, developers, architects, contractors and retrofit coordinators.

What we do on retrofit jobs

• EPCs before and after the work. The before EPC shows where the building stands and which measures move the rating most. The after EPC records the result. For homes see our SAP calculations and EPCs; for offices, shops and other buildings see commercial EPCs.
• SAP and SBEM calculations. Conversions and major refurbishments often need a full calculation for building control. We model the design before work starts, so the specification is right first time. SAP calculations from £100+VAT; SBEM calculations from £400+VAT.
• U-value calculations. When you insulate a wall, floor or roof, or replace windows, building control can ask for evidence that the new build-up meets Part L. We calculate it from your specification.
• EPC upgrade plans. For commercial landlords facing EPC B from 2031, our EPC B upgrade plan (from £700+VAT) sets out the measures, what each one does to the rating and the order to do them in.
• Air tightness testing. Retrofit often makes a building more airtight. An air test shows where you are and is often asked for on conversions.
• Ventilation testing. More airtight means ventilation matters more. We measure extract fan and system flow rates against Part F with ventilation testing.
• Sound testing for conversions. Converting a building into flats needs sound insulation testing between the new homes.
• Air conditioning and DECs. If a refurbished building has air conditioning or is a public building, we carry out TM44 inspections and DECs.

Why ventilation needs checking

Approved Document F says energy efficiency work must not leave a home with worse ventilation than before, and that after the work it should still meet the minimum standard. Insulation, new windows and draught-proofing all reduce air leakage, so the ventilation that was enough before may not be enough after. Checking it with an air test and fan flow measurements avoids condensation and mould later.

Funded schemes and PAS 2035

Government-funded home retrofit, such as the Energy Company Obligation, follows the PAS 2035 process and uses TrustMark registered installers, with a retrofit assessment and a retrofit coordinator on each project. We do not act as retrofit coordinator. We provide the EPCs, energy calculations and testing that coordinators, installers and building control ask for, and we can work alongside the team you already have.

Why landlords are looking at retrofit now

The government has confirmed that privately rented homes must reach EPC C by 1 October 2030, and that rented commercial buildings over 1,000 m² will need EPC B from 2031 where cost effective. The details and sources are on our industry updates page. Planning the work around an accurate EPC is cheaper than guessing.

What we need from you

Floor plans or a site visit, what is there now (walls, roof, windows, heating, hot water), and what you plan to change. For a commercial building, the floor area and building use. We come back with a price and a turnaround time.

Questions we get asked

Do I need an EPC before I start? It is not always required, but it is the best starting point. It shows which measures move the rating and gives you a baseline to compare against.

Are you a retrofit coordinator? No. We are energy assessors. We provide the EPCs, calculations and tests that the retrofit coordinator, installer and building control need.

Will insulation make my home damp? It can if ventilation is not dealt with. That is why Part F asks for ventilation to be no worse after the work, and why we recommend checking it with an air test and fan flow measurements.

Can you book the air test and ventilation test together? Yes, and booking them together costs less because it saves a second visit.

More: SAP calculations and EPCs, commercial EPCs, EPC B upgrade plans, air, sound and ventilation testing, EPC B by 2031 guide, industry updates

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