Part G water efficiency calculation factors v1.0 · 22 Aug 2026
The complete Table 1 of The Water Efficiency Calculator for New Dwellings (DCLG, 2009) — the methodology required by Approved Document G and Building Regulation 36 — plus the 0.91 normalisation factor, the fixed 5 l/p/d external-use allowance, the unspecified-appliance defaults and the multiple-fittings averaging rule. These are the exact constants WaterMonkey calculates with, cross-checked against the published document.
Prefer it explained? The factors are worked through fitting by fitting in the no-spreadsheet guide, with a full worked example from fittings schedule to final figure.
England nutrient-neutrality catchments v1.0 · 2 Sep 2026
All 27 nutrient-neutrality catchments in England: the protected site each one serves, whether it is assessed for nitrogen or phosphorus (or both), the counties it reaches, and the official credit price where a scheme publishes one — 10 of the 27 do. Plus the constants every nutrient budget uses: Natural England's 2.4 persons-per-dwelling default, the +10 l/p/d water-use allowance and the 20% precautionary buffer. Prices and catchment boundaries both move, so every row carries the scheme name and its caveats alongside the number — and an empty price means not published, never zero.
Wastewater treatment works permit consents v1.0 · 19 Sep 2026
The nitrogen and phosphorus permit consents — current, post-2025 and post-2030 — for 675 wastewater treatment works across 22 nutrient neutrality catchments, taken from Table 1, the Stage 1 WwTW lookup, of Natural England's published catchment calculators. Every row carries the workbook it came from. This is the number that decides the size of a nutrient budget, and Natural England publish it in 22 separate spreadsheets; 193 of the 675 tighten by 2030 under WINEP. Browse it on the permit register, or take the whole thing:
Thermal conductivity (λ) library v1.0 · 19 Sep 2026
418 λ-values — 53 generic construction materials and 365 named UK products from 108 manufacturers — each carrying the document it was read from, what kind of source that is (a maker's declaration, a BBA certificate, a retailer listing, a paywalled standard) and the date it was retrieved. 324 come from a declaration or a certificate. There is no other neutral, sourced UK list of these numbers: manufacturers publish one product at a time and the standards are behind a paywall. Browse it in the thermal conductivity library, or take the lot:
RdSAP 10 age bands and default U-values v1.0 · 20 Sep 2026
1,885 wall U-values — 29 wall types × 13 age bands × five countries, from RdSAP 10 Tables 6–10 — plus Table 1 (the age bands themselves, by country, including park homes), Table 18 (assumed roof U-values) and 458 more values covering every other U-value table in the specification: party walls, roofs and rooms in roof by measured insulation thickness, ground and exposed floors, thermal bridging, wall thickness, the stone and brick equations the early age bands defer to, park home walls, insulation resistance, thermal mass, basements, windows, conservatories and doors. These are the figures every EPC on an existing home falls back on when the construction cannot be evidenced, and they are published only inside a 106-page PDF. Footnote markers and the “calculate from section 6.6/6.7/6.8” cross-references are kept as their own columns rather than flattened away. Browse it with a year-to-band lookup on the RdSAP age bands page.
Walls CSV Walls JSON Age bands CSV Roofs CSV Element defaults CSV Lookup tables CSV
Source: RdSAP10 Specification, BRE, 12 February 2024. Reproduced with attribution; the specification is the authority for a lodged assessment. Energycount does not carry out RdSAP assessments; this is published as a reference.
UK carbon conversion factors 2026 v1.0 · 19 Sep 2026
The 913 factors a building project uses, out of the 8,740 the UK Government publishes — fuels, electricity generation, transmission and distribution losses, well-to-tank, heat and steam, water supply and treatment, waste, materials and refrigerants. The official release is a workbook that is mostly vehicles and freight; this is the part you need, with the year and version on it. Browse it on the carbon factors page, which also explains why these are not the SAP Table 12 factors.
Contains public sector information licensed under the Open Government Licence v3.0. Taken from the flat file as revised on 31 July 2026 — the first release reported a number of values as zero.
Declared λ-values are facts about products, published here with their citation — no datasheet text or artwork is reproduced. Where the only source is a paywalled value table the row says so rather than passing the figure off as confirmed.
Contains public sector information licensed under the Open Government Licence v3.0. Natural England's calculators remain the statutory tool — a permit can be varied at any time, so confirm the consent that decides your scheme against the current workbook.
Every row carries a link to that catchment's page, where the free nutrient neutrality calculator runs the budget for you — occupancy, water use, concentrations and the 20% buffer.
Licence & citation
Everything on this page is published under CC BY 4.0 — free to reuse, including commercially, with attribution to energycount.co.uk. The underlying figures are Crown-published methodology values and public-body designations; the licence covers our verified machine-readable arrangement of them. Suggested citation:
Energycount (2026). UK building-compliance open data (v1.0). https://energycount.co.uk/data/ — accessed [date].
Spotted an error, or want another compliance dataset published (Part L limiting U-values, SAP default Ψ-values, BRE 365 storm data)? Tell us — this page will grow.