What signals does a solar prospect file actually contain?
Most solar prospect data originates from two sources: home-improvement and lifestyle surveys where respondents ticked a box indicating interest in solar panels or renewable energy, and follow-on surveys sent to households that had already declared an interest in green home improvements. A smaller share of records come from prize-draw entries where entrants opted in to hear from energy and utilities companies specifically.
The declared-interest field is not the whole picture. Raw green-energy interest captures a wide spread of households, from a retired couple in a Stockport semi who want to cut bills, to a 28-year-old renting a city flat who read an article about net zero. The renter in the flat has no realistic prospect of installing panels. Good prospect data filters that raw pool against structural signals before any record reaches a campaign file.
The four structural signals that matter are: tenure, property type, income band, and opt-in recency. Each one cuts the universe significantly. Used together, they produce a file where the records that remain have a plausible path to purchase.
The four filtering signals in detail
Signal 1: Owner-occupier tenure
Tenure is the single most important filter. Private renters and most social housing tenants cannot install solar panels without landlord consent, and even where a landlord agrees, the financial return accrues to the occupier rather than the property owner, which creates a practical barrier that kills most conversations. Owner-occupiers are the correct target universe.
UK consumer files capture tenure through a combination of self-declared responses on lifestyle surveys, Land Registry title data overlaid at household level, and geodemographic modelling. The most reliable tenure signal is self-declared owner-occupier status from the survey itself, ideally with a property ownership question separate from the interest-in-solar question. See our article on UK homeowner data: sources, accuracy, and use cases for more detail on how ownership status is verified and what accuracy to expect at postcode level.
Signal 2: Property type
Not all owner-occupied properties are equally suitable for solar installation. Detached houses have the highest installation rates in the UK because they typically offer unobstructed roof access and no shared-wall complications. Semi-detached houses follow closely. Mid-terrace properties are viable but carry a higher rejection rate at the survey stage because roof orientation and shared ridge lines complicate standard installations.
Purpose-built flats and maisonettes are almost universally excluded from solar prospect files. The roof rights sit with the freeholder, not the leaseholder, and the practical barriers to a block-wide installation are significant. Converted flats occupy a grey area: if the individual owns the freehold share and has roof access rights, installation is possible, but these are a small fraction of the flat population.
Property type is generally available on consumer data files derived from Royal Mail's Postcode Address File (PAF) combined with land use classifications. The field is not always self-declared but inferred from address structure, so treat it as a filter to reduce the pool rather than a guarantee of suitability.
Signal 3: Declared green-energy interest
The green-energy interest flag itself comes directly from the survey questionnaire. The most common question formats ask respondents to select which home-improvement topics they want information about, with solar panels, heat pumps, insulation, and EV charging typically appearing as separate options. Respondents who ticked solar specifically are a stronger signal than those who ticked the broader "renewable energy" or "green home" bucket.
In our experience, the highest-converting sub-segment within solar prospect files is the group that ticked both "solar panels" and "home improvements in the next 12 months" on the same survey. That combination flags genuine near-term intent rather than ambient environmental interest. Ask your data supplier whether intent timing is available as a separate field.
Signal 4: Household income or affluence band
A standard domestic solar installation in the UK cost roughly £5,000 to £9,000 for a 4 kWp system in early 2026. Finance products, including the Green Deal successor schemes and various lender offers, have lowered the cash barrier for some households, but upfront affordability remains the primary objection to purchase. Targeting households with estimated household income below £25,000 per year produces a pool that is harder to convert and more dependent on grant or finance availability.
Most UK consumer files carry an estimated income band derived from Census 2021 outputs, ONS earnings by occupation, and property value scoring at output area level. This is a modelled figure, not a declared one. It is accurate enough to segment the population into rough affordability tiers, but not precise enough to underwrite credit decisions. For solar, the practical threshold is household income above approximately £28,000 to £35,000, or a council tax band of D or above as a proxy. See our article on how UK consumer income data is compiled for the methodology behind these estimates.
Volume estimates and what drives them
Applying all four filters to the UK's fully opt-in consumer file produces a solar prospect universe of roughly 1.5 to 2.5 million households. That range reflects variation in how tightly suppliers define "green-energy interest" and which property type classifications they include. The table below shows how each filter progressively reduces the available count from the starting point of UK owner-occupied households with a declared survey opt-in for energy or home-improvement marketing.
| Filter stage | Filter applied | Approximate remaining count | Notes |
|---|---|---|---|
| Starting universe | All opt-in adult UK consumer records | 10M+ records | Fully opt-in file under UK GDPR and PECR consent |
| Filter 1 | Owner-occupier tenure only | ~5.5M to 6M | Removes private renters, social housing, flat sharers |
| Filter 2 | Detached, semi-detached, or mid-terrace property type | ~4M to 4.5M | Removes flats, maisonettes, and non-residential address types |
| Filter 3 | Declared solar or green-energy interest on survey | ~2.5M to 3.5M | Range depends on breadth of interest category used |
| Filter 4 | Household income band £28K+ or council tax band D+ | ~1.5M to 2.5M | Core prospect file; highest conversion potential |
| Optional add | ECO4-eligible: low income plus owner-occupier or private rented | ~200K to 400K | Distinct sub-segment for funded-scheme campaigns |
These are count estimates based on a fully opt-in consumer file of 10M+ UK records. Actual counts vary by supplier, suppression file applied, and whether the file has been recently refreshed. Always request a live count against your specific criteria before committing to a volume.
Combining with property data and income data
The four-signal approach above is a good starting point, but solar panel campaigns typically benefit from a further layer of property-level enrichment. Three additional data points sharpen the file without dramatically reducing volume.
Council tax band. Band D (typically properties worth £68,001 to £88,000 at the 1991 reference date, which maps to roughly £250,000 to £400,000 in current values for most English regions) and above is a strong proxy for a property size and capital value sufficient to support a viable installation. Council tax band is available on most consumer files derived from VOA (Valuation Office Agency) data and does not require a declared income question.
Length of residency. Households that have lived at the same address for more than five years are more likely to invest in permanent improvements. Someone who moved in six months ago is unlikely to be planning a £7,000 solar installation. Residency duration is a standard field on most consumer files and cuts approximately 15 to 20% of otherwise-qualified records when set to five years or more.
Family lifecycle stage. Households with children aged 5 to 16 tend to over-index on solar interest because energy bills are typically higher and there is a financial planning horizon that makes a 15-year payback calculation more attractive. This is a geodemographic or survey-derived field rather than a hard fact, but it is a useful scoring variable if you want to weight outreach rather than hard-exclude records.
For property-level enrichment specifically, our article on UK consumer property data covers the full range of fields available and how they are compiled (forthcoming).
Refresh cycles for green-energy interest data
Declared interest data has a shorter useful life than demographic fields. A household's postcode, tenure, and property type rarely change. But their stated willingness to hear from solar suppliers can shift significantly within 12 to 18 months, for reasons including: completing an installation, deciding they cannot afford it, moving house, or simply losing interest after the initial survey.
The practical minimum for green-energy interest data is a 12-month refresh cycle. For high-volume direct mail campaigns (above 200,000 pieces), it is worth asking your data supplier to filter by survey recency, typically supplied as the month and year of the opt-in response. Records where the opt-in is less than 12 months old will consistently outperform records where it is 18 to 24 months old, sometimes by a factor of 2 on response rate.
There is a further complication specific to the solar market. UK government policy around solar grants, VAT relief (which dropped to 0% on residential installations from April 2022 under the Spring Statement, then extended by subsequent fiscal events), and the Smart Export Guarantee (SEG) export tariff all affect consumer appetite in ways that are difficult to capture at the survey level. A household that was not interested in solar when the VAT rate was 5% may have become interested after it dropped to zero. Survey data cannot always keep pace with policy changes, so pairing the prospect file with a telemarketing first-touch (to verify current interest) often improves downstream conversion on direct mail or digital campaigns.
ECO4 and UK government scheme targeting
The Energy Company Obligation 4 (ECO4) scheme, which runs to March 2026 in its current form, requires energy suppliers to fund insulation and heating measures for low-income households. Solar panels are not the primary focus of ECO4, but the scheme shares its target demographic with the lower end of the solar prospect market: owner-occupiers and private renters with lower incomes who receive means-tested benefits such as Universal Credit, Pension Credit, or Child Tax Credit.
Identifying ECO4-eligible households within a consumer file requires three flags working together: low estimated income band, owner-occupier or private-rented tenure, and either a declared benefits flag or a geodemographic score placing the postcode in a lower-income decile. Not all consumer files carry a benefits flag, and where it does exist it is typically self-declared from the survey rather than sourced from HMRC or DWP records. That means coverage is partial: perhaps 40 to 60% of genuinely benefit-receiving households in the file will carry the flag.
For campaigns focused on ECO4 or the Warm Homes Plan (its likely successor under current DESNZ consultations), the more reliable approach is to combine a low-income geodemographic score with a postcode-level deprivation index (the Index of Multiple Deprivation for England, or equivalent for Scotland, Wales, and Northern Ireland) rather than relying on a sparse declared-benefits field. That geodemographic approach will produce a cleaner and more complete count than trying to isolate declared-benefits records alone.
The Great British Insulation Scheme and the Boiler Upgrade Scheme (BUS), which pays grants toward heat pump installations, have their own eligibility criteria that are partially addressable through consumer data. BUS, in particular, targets a higher-income homeowner who could afford the remaining cost after the grant, making it a near-perfect match for the upper end of the solar prospect file rather than the ECO4 sub-segment.
Target segment table: matching data filters to campaign type
Different solar campaigns call for different slices of the prospect universe. The table below maps common campaign types to the data selections that support them.
| Campaign type | Key data filters | Approximate UK count | Channel recommendation |
|---|---|---|---|
| Standard residential solar installation (self-funded) | Owner-occupier, detached/semi, green-energy interest, income band £35K+, council tax band D+ | 900K to 1.2M | Direct mail lead, email or telephone follow-up |
| Finance-assisted solar installation | Owner-occupier, detached/semi/terrace, green-energy interest, income band £25K-£35K, age 35 to 64 | 500K to 800K | Direct mail with finance offer prominent |
| Battery storage or EV charger cross-sell | Owner-occupier, existing solar panel flag, EV interest or declared EV owner | 80K to 200K | Email or telephone; higher engagement expected |
| ECO4 / Warm Homes funded scheme | Owner-occupier or private rented, low income band or IMD decile 1-3, benefits flag where available | 200K to 400K | Direct mail; telephone to verify eligibility before visit |
| Boiler Upgrade Scheme (heat pump) crossover | Owner-occupier, detached/semi, income band £45K+, green-energy or renewable-heat interest | 400K to 600K | Direct mail; specialist landing page for grant calculator |
Compliance considerations for solar prospect campaigns
Solar marketing sits firmly within direct marketing regulation. Because the records on a fully opt-in consumer file carry consent under Article 6(1)(a) UK GDPR plus PECR consent for the relevant electronic channel, the buyer inherits the lawful basis from the supplier. That does not eliminate compliance obligations on the buyer's side.
Before any telephone campaign using solar prospect data, the list must be washed against the Telephone Preference Service (TPS) every 28 days as required by the Privacy and Electronic Communications Regulations (PECR). Individual records that have registered with TPS after their original opt-in cannot be called. The TPS wash does not override the original consent for postal or email contact, but it is mandatory for telephone before each campaign run.
The Information Commissioner's Office (ICO) has historically taken a close interest in solar and home-improvement marketing due to high complaint volumes in the sector. In practice this means two things: your Article 14 notice (telling recipients you obtained their data from a third party) should be clear and timely, and your suppression process for opt-outs must be permanent and cross-channel. A recipient who opts out from a postal piece should not receive a follow-up telephone call from the same campaign.
For a full walkthrough of the buyer's GDPR obligations when using purchased consumer data, see our guide on what the ICO says about buying marketing data.