| Measure | Grant | Net cost | Saving / yr | Payback | Grade effect |
|---|---|---|---|---|---|
| High-retention storage heaters | — | £1,200 – £1,800 | £355 | 4.2 yrs | +11.1 pts |
| Cavity wall insulation | — | £500 – £1,500 | £134 | 7.4 yrs | +4.2 pts · reaches C |
| Floor insulation(optional, beyond C) | — | £4,000 – £6,000 | £180 | 27.8 yrs | +5.6 pts |
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 £489 a year — a 19.6% annual return on £2,500.
Restated at the fuel prices assumed in July 2026. This certificate, assessed in 2022, states £945 a year at the prices assumed then. Modelled costs, not a bill.
Sold prices
Estimated today: £227,467 HPI-indexed estimate, not a valuation
Chalfont Close: 139 sales since 1995 · £302,482 average over 10 years
Schools nearby
The schools’ own performance — Progress 8 shows value added, not just raw results.
| School | Phase | Distance | Progress |
|---|---|---|---|
| Holtsmere End Junior School | Primary | 0.1 mi | — |
| Holtsmere End Infant and Nursery School | Primary | 0.1 mi | — |
| Brockswood Primary School | Primary | 0.4 mi | — |
| The Astley Cooper School | Secondary | 0.4 mi | Progress 8 -0.60 · well below average (2023/24) |
| The Adeyfield Academy | Secondary | 1.6 mi | Progress 8 -0.97 · well below average (2023/24) |
| Laureate Academy | Secondary | 2.3 mi | Progress 8 -0.22 · below 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 E01023434, to 2026-06. An LSOA holds about 1,500 people, so this covers far more than one street.
Chalfont Close
How this home sits against its street.