| Measure | Grant | Net cost | Saving / yr | Payback | Grade effect |
|---|---|---|---|---|---|
| Loft insulation | — | £100 – £350 | £68 | 3.3 yrs | +2.8 pts |
| Floor insulation | — | £800 – £1,200 | £142 | 7.0 yrs | +5.9 pts · reaches E |
| Heating controls | — | £350 – £450 | £52 | 7.7 yrs | +2.2 pts |
| Change of heating system | — | £3,000 – £7,000 | £405 | 12.3 yrs | +17.0 pts · reaches D |
| Solar water heating | — | £4,000 – £6,000 | £110 | 45.4 yrs | +4.6 pts |
| Solar photovoltaic panels | — | £5,000 – £8,000 | £131 | 49.5 yrs | +5.5 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 £908 a year — a 5.0% annual return on £18,125.
Restated at the fuel prices assumed in July 2026. This certificate, assessed in 2017, states £1,665 a year at the prices assumed then. Modelled costs, not a bill.
Sold prices
Estimated today: £866,158 HPI-indexed estimate, not a valuation
Mark Drive: 4 sales since 1995 · £730,100 average over 10 years
Schools nearby
The schools’ own performance — Progress 8 shows value added, not just raw results.
| School | Phase | Distance | Progress |
|---|---|---|---|
| Robertswood School | Primary | 0.8 mi | — |
| Chalfont St Giles Infant School and Nursery | Primary | 0.9 mi | — |
| Chalfont St Giles Junior School | Primary | 0.9 mi | — |
| The Chalfonts Community College | Secondary | 1.0 mi | Progress 8 -0.54 · well below average (2023/24) |
| The Reach Free School | Secondary | 2.4 mi | Progress 8 -0.02 · average (2023/24) |
| Dr Challoner's High School | Secondary | 3.1 mi | Progress 8 +1.11 · well above 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 E01017758, to 2026-05. An LSOA holds about 1,500 people, so this covers far more than one street.
Mark Drive
How this home sits against its street.