Understanding Data Sources

Redbook Assist fetches data from six external sources when you add a property. Here is what each provides and its limitations.

EPC (Energy Performance Certificates)

Source: epc.opendatacommunities.org (DLUHC Open Data)

Provides:

• Current energy rating (A to G) and score
• Potential energy rating
• Floor area (total useful floor area in square metres)
• Property type, built form, and construction age band
• Heating system description
• Recommendations for improvement

Limitations:

• Only properties with an EPC since 2008 are included
• Address matching relies on exact postal address — flats may need the full unit description
• EPC floor area can differ from measured surveys by 5-15%

Land Registry (Price Paid Data)

Source: HM Land Registry Open Data via SPARQL endpoint

Provides:

• Historical transaction prices with dates
• Property type and tenure at time of sale
• Whether the sale was a new build

Limitations:

• Only includes residential sales in England and Wales
• Commercial transactions are not in the open dataset
• New transactions take 2-4 months to appear
• Does not include properties sold for less than market value (e.g. right-to-buy transfers at discount)

Flood Risk

Source: Environment Agency Flood Map for Planning API

Provides:

• Flood zone classification (Zone 1, 2, 3, or 3b)
• Flood area boundaries
• Risk level assessment

Limitations:

• Covers England only (not Wales, Scotland, or Northern Ireland)
• Flood zones are modelled — actual risk may differ from the classification
• Surface water flood risk is not included (only river and coastal)

Planning

Source: PlanIt API + Historic England

Provides:

• Recent planning applications within the vicinity
• Conservation area status
• Listed building grade (I, II*, II)
• Article 4 directions

Limitations:

• Coverage depends on the local planning authority publishing data
• Some smaller authorities have incomplete digital records
• Applications older than 5 years may not appear

VOA (Valuation Office Agency)

Source: Imported from VOA Rating List 2023 (2.3 million commercial properties)

Provides:

• Rateable value from the 2023 rating list
• Floor area (gross internal area)
• Market rent analysis factors
• Property description and use class

Limitations:

• Commercial properties only — residential properties will not have VOA data
• Based on the 2023 rating list with a valuation date of 1 April 2021
• Floor areas are scheme areas, not necessarily GIA as measured

Street View

Source: Google Street View Static API

Provides:

• Street-level photograph of the property
• Adjustable heading and field of view

Limitations:

• Coverage is not universal — rural areas and new developments may lack imagery
• Images may be several years old
• The default camera position may not show the property clearly (you can adjust the heading manually)
• Interior images are not available