A retrofit assessment — formally a Whole Dwelling Assessment carried out under PAS 2035 — typically costs £150–£500 for a straightforward home in 2026 if you're commissioning and paying for it yourself, rising to £500–£900 or more for a larger, more complex or traditionally-built property that needs a longer site visit and closer fabric investigation. If your retrofit is being carried out through a funded route — ECO4 or the Warm Homes: Local Grant — the assessment cost is built into the scheme's funding and you won't see a bill for it at all.
That headline figure is where most confusion starts, because it's easy to conflate with two other things: the cost of a Retrofit Coordinator, a separate role charging a separate fee, typically £500–£1,500 and sometimes more on a bigger project; and the cost of the retrofit work itself, which is a different number again and depends entirely on what the assessment recommends. The assessment fee is just the diagnosis — the document the rest of the project gets built against.
I should say upfront: I'm a TrustMark/Elmhurst-registered Retrofit Assessor and offer this as part of my own practice, so I have a direct interest in this one that I don't have in most of what I write about here. What follows is still checked against the wider UK market rather than just my own price list, and I've tried to be as honest about when you don't need the full PAS 2035 process as I am about when you do.
The short answer
Figures below were checked on 1 September 2026 against current UK retrofit assessor and coordinator pricing, cross-referenced against each other and against my own fee structure. As with the rest of this series, quotes in London and the South East — my own patch included — commonly trend above the rest of the country for a comparable job.
| Route | Typical cost (2026) | What's included |
|---|---|---|
| Self-funded, straightforward home | £150–£500 | Whole Dwelling Assessment, occupancy review, condition & risk evaluation, improvement plan |
| Self-funded, larger, complex or traditionally-built | £500–£900+ | Longer site visit, deeper fabric investigation, breathability/hygrothermal considerations |
| Retrofit Coordinator (separate role) | £500–£1,500+ | Project management, sequencing installers, sign-off through to completion |
| ECO4 or Warm Homes: Local Grant funded | £0 to the homeowner | Assessment and coordination cost built into the scheme's own funding |
Some retrofit companies quote assessor and coordinator work as a single bundled figure, which can run to several hundred pounds more than the assessment alone once project management, a written medium-term plan and any data-warehouse lodgement are folded in. That's not necessarily bad value if you want one point of contact managing the whole job — but it's a different product from a stand-alone assessment, and worth knowing which one you're being quoted for.
What drives the price
Size of the dwelling. More floor area and more rooms means more measurements, more photographs and a longer site visit — typically one to three hours on-site depending on the property.
Traditional or unusual construction. Solid-wall, timber-frame or listed homes need a closer look at what the fabric is actually doing before insulation measures can be modelled safely, which adds time on site and in the report. This is where the fee moves from the bottom of the range to the top.
Assessor versus assessor-plus-coordinator. A stand-alone Whole Dwelling Assessment is the cheaper end of this market; bundling in coordination through to completion is a separate, larger fee for a separate scope of work.
Report depth and lodgement. A full PAS 2035 pack — occupancy assessment, condition and risk evaluation, medium-term improvement plan, and lodgement to the relevant data warehouse where the funding route requires it — costs more to produce than a bare energy calculation.
Travel and region. A property well outside an assessor's normal patch can carry a small mobilisation cost, and the South East generally trends above the England-wide average for this kind of work.
Revisits. If access to part of the fabric — a loft, a subfloor, an outbuilding — isn't available on the first visit, a second site visit adds to the fee. Confirming access in advance avoids this.
Do you actually need one?
It depends entirely on the route into the work. If you're applying for ECO4 funding or the Warm Homes: Local Grant, a retrofit assessment is mandatory — no assessment, no funded measures, full stop. It's also genuinely useful evidence, though not legally required, if you're a landlord registering a MEES exemption on a hard-to-treat property, since the exemption register wants a proper written case for why a measure would harm the building or cost too much, not just an assertion.
For a self-funded project, the honest answer is that it becomes worthwhile once you're spending £10k or more on fabric or systems, or planning several measures across more than one visit from different trades. At that scale, a proper sequence — ventilation and moisture risk addressed before insulation goes in, for instance — is the difference between a retrofit that works and one that traps damp in the wall for the next occupant to find. For a single, well-understood measure on a straightforward property — topping up loft insulation that's already there, swapping a like-for-like boiler — the full PAS 2035 process is more than most homeowners need, and I'll say so if that's what someone asks me to look at.
If the work is grant-funded
ECO4 is running to 31 December 2026, extended from its original March 2026 end date, after which it closes without a direct successor supplier obligation. The Great British Insulation Scheme closed on 31 March 2026 and has not reopened. In its place, the Warm Homes: Local Grant, administered council by council, runs to March 2028 and covers eligible owner-occupier and privately-rented households: broadly, a gross household income of £36,000 or less, or a home in one of the lowest-income deprivation deciles, or a household already receiving a qualifying means-tested benefit, with the property itself rated EPC D–G. Funding under the scheme can run up to £30,000 per property, and where a household qualifies, the retrofit assessment and coordination cost is explicitly part of that funding, not a separate bill.
If you're not sure which route you fall into, it's worth checking with your local council before commissioning a self-funded assessment — there's no point paying for a Whole Dwelling Assessment out of your own pocket if a funded route would have covered it, though the two aren't always interchangeable once work is under way.
What I'd watch for in a quote
- Confirm exactly what's being quoted — the Whole Dwelling Assessment alone, or assessment and coordination bundled into one figure.
- Ask for the assessor's registration under a recognised scheme (TrustMark, Elmhurst or equivalent) and confirmation the work follows the current PAS 2035:2023 edition specifically.
- Check the report includes all four pillars — Whole Dwelling Assessment, occupancy assessment, condition and risk evaluation, and a medium-term improvement plan — not just an energy calculation with a product list attached.
- Ask whether lodgement to the relevant data warehouse is included, where your funding route requires it.
- Get a fixed fee before the visit, and ask what a revisit costs if part of the property can't be fully assessed the first time.
- For traditional or listed buildings, ask directly about breathability — whether the assessor is modelling as-built performance for solid-wall or lime construction, rather than applying modern-build assumptions to an old building.
Questions I get asked
How much does a PAS 2035 retrofit assessment cost in 2026? If you're paying for it yourself, typically £150–£500 for a straightforward home, rising to £500–£900 or more for a larger, complex or traditionally-built property needing extra fabric investigation. If the work is funded through ECO4 or the Warm Homes: Local Grant, the assessment is included in the scheme funding and costs the homeowner nothing directly.
Do I need a retrofit assessment if I'm not applying for a grant? Not legally, but it's worth having if you're spending £10k or more on fabric or systems and want the work properly sequenced, or if you need evidence for a MEES exemption on a hard-to-treat property. Below that, a single, well-understood measure — a loft top-up, a straightforward boiler swap — rarely needs the full PAS 2035 process.
What's the difference between a retrofit assessor and a retrofit coordinator, and why does it matter for cost? The assessor produces the Whole Dwelling Assessment that measures and models the building; the coordinator manages the project against that assessment through to completion, and charges a separate fee, typically £500–£1,500 or more depending on scale. Quotes that bundle or conflate the two figures can make either service look artificially expensive.
Is the assessment free if my retrofit work is grant-funded? Usually yes. Under ECO4, running to 31 December 2026, and Warm Homes: Local Grant, running to March 2028 for eligible households, the retrofit assessment and coordination cost sits inside the scheme's funding rather than being billed to you directly. It only becomes a bill you pay yourself once you're outside a funded route.
A retrofit assessment is the document the rest of a project gets designed against, whether that's an ECO4 installer, a Retrofit Coordinator you've hired separately, or just your own decision-making on a self-funded job. If you'd like one carried out on a straightforward home or a trickier traditionally-built property, that's my PAS 2035 retrofit assessment work, and I also handle the EPC end of the same energy picture. Call 07946 618203 or get in touch and I'll come back the same day with a fixed fee.
Small print. This guide is general information, not advice on a specific property or funding route, and it doesn't replace a written quote from a qualified assessor for your own situation. I offer retrofit assessments myself, as noted above; the pricing here is checked against the wider market, not just my own rates. Prices were researched and correct to the best of my knowledge on 1 September 2026; costs, grant schemes and eligibility rules move and vary by region and council. Always confirm current grant eligibility with your local authority before committing to a self-funded assessment.