| Measure | Grant | Net cost | Saving / yr | Payback | Grade effect |
|---|---|---|---|---|---|
| Floor insulation | — | £1,200 – £200 | £189 | 3.7 yrs | +8.6 pts |
| Change of heating system | — | £7,000 – £0 | £541 | 6.5 yrs | +24.4 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 £730 a year — a 17.4% annual return on £4,200.
Energy costs as modelled on the certificate, not a bill. This fuel has too few recent certificates to restate at today's prices.
Sold prices
Estimated today: £192,491 HPI-indexed estimate, not a valuation
Carronade Walk: 31 sales since 1995 · £170,333 average over 10 years
Schools nearby
The schools’ own performance — Progress 8 shows value added, not just raw results.
| School | Phase | Distance | Progress |
|---|---|---|---|
| Highbury Primary School | Primary | 0.4 mi | — |
| Gatcombe Park Primary School | Primary | 0.4 mi | — |
| King's Academy Northern Parade (Junior) | Primary | 0.6 mi | — |
| UTC Portsmouth | Secondary | 0.3 mi | Progress 8 -0.47 · below average (2023/24) |
| Trafalgar School | Secondary | 0.3 mi | Progress 8 -0.19 · average (2023/24) |
| Springfield School | Secondary | 1.0 mi | Progress 8 -0.05 · 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 E01017090, to 2026-06. An LSOA holds about 1,500 people, so this covers far more than one street.
Carronade Walk
How this home sits against its street.