| Measure | Grant | Net cost | Saving / yr | Payback | Grade effect |
|---|---|---|---|---|---|
| Cavity wall insulation | — | £1,500 – £500 | £96 | 10.4 yrs | +5.8 pts |
| Solar water heating | — | £6,000 – £0 | £99 | 30.2 yrs | +6.0 pts · reaches C |
| Solar photovoltaic panels | — | £8,000 – £0 | £119 | 33.7 yrs | +7.2 pts · reaches B |
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 £314 a year — a 3.9% annual return on £8,000.
Restated at the fuel prices assumed in July 2026. This certificate, assessed in 2015, states £859 a year at the prices assumed then. Modelled costs, not a bill.
Sold prices
Estimated today: £412,426 HPI-indexed estimate, not a valuation
Thirlmere Gardens: 146 sales since 1995 · £445,952 average over 10 years
Schools nearby
The schools’ own performance — Progress 8 shows value added, not just raw results.
| School | Phase | Distance | Progress |
|---|---|---|---|
| Holy Trinity CofE Primary School | Primary | 0.2 mi | — |
| Frithwood Primary School | Primary | 1.0 mi | — |
| Eastbury Farm Primary School | Primary | 1.1 mi | — |
| Harefield School | Secondary | 1.7 mi | Progress 8 -0.66 · well below average (2023/24) |
| UTC Heathrow | Secondary | 1.7 mi | Progress 8 -1.61 · well below average (2023/24) |
| Northwood School | Secondary | 1.8 mi | Progress 8 +0.76 · 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 E01002475, to 2026-06. An LSOA holds about 1,500 people, so this covers far more than one street.
Thirlmere Gardens
How this home sits against its street.