| Measure | Grant | Net cost | Saving / yr | Payback | Grade effect |
|---|---|---|---|---|---|
| Low energy lighting | — | £40 | £21 | 1.9 yrs | +0.3 pts |
| Floor insulation | — | £800 – £1,200 | £487 | 2.1 yrs | +6.9 pts · reaches D |
| Flat roof insulation | — | £850 – £1,500 | £370 | 3.2 yrs | +5.3 pts |
| Solid wall insulation | — | £4,000 – £14,000 | £526 | 17.1 yrs | +7.5 pts · reaches C |
Grants verified 20 August 2026. Costs are the register’s indicative ranges. Savings are restated at the fuel prices assumed in July 2026. Points per measure are estimated from 19.9 million certificates and rescaled to this home’s own certificate delta; the total is the register’s figure.
Running costs
The full plan saves £1,404 a year — a 12.5% annual return on £11,215.
Restated at the fuel prices assumed in July 2026. This certificate, assessed in 2023, states £3,718 a year at the prices assumed then. Modelled costs, not a bill.
Sold prices
Estimated today: £959,971 HPI-indexed estimate, not a valuation
Portnall Drive: 51 sales since 1995 · £2,537,933 average over 10 years
Schools nearby
The schools’ own performance — Progress 8 shows value added, not just raw results.
| School | Phase | Distance | Progress |
|---|---|---|---|
| Trumps Green Infant School | Primary | 1.2 mi | — |
| Holy Trinity CofE Primary School, Sunningdale | Primary | 1.5 mi | — |
| St Ann's Heath Junior School | Primary | 1.8 mi | — |
| Charters School | Secondary | 2.3 mi | Progress 8 +0.25 · above average (2023/24) |
| Salesian School, Chertsey | Secondary | 3.6 mi | Progress 8 +0.96 · well above average (2023/24) |
| The Magna Carta School | Secondary | 3.9 mi | Progress 8 +0.13 · average (2023/24) |
Schools from the DfE register, performance from the KS4 performance tables. Progress 8 is a GCSE measure, so primaries have none. Distance is straight-line from the postcode, not a catchment: admission is decided by the school, not by us.
Area context
Police-recorded crime for the wider neighbourhood, not this address. We grade homes, never neighbourhoods — so this is reported as a count, not a rating.
Police.uk street-level data for LSOA E01030692, to 2026-06. An LSOA holds about 1,500 people, so this covers far more than one street.
Portnall Drive
How this home sits against its street.