{
  "version": "2026-08-29.1",
  "checked_date": "2026-08-29",
  "demand": {
    "loft_insulation_cost": {
      "country": "UK",
      "observed_bin": ">1,000 monthly",
      "difficulty": "Easy",
      "source": "AHREFS_FREE_MEASUREMENTS_2026-08-29.csv",
      "note": "Observed demand bin, not exact volume or a traffic forecast."
    },
    "cavity_wall_insulation_cost": {
      "country": "UK",
      "observed_bin": ">1,000 monthly",
      "difficulty": "Easy",
      "source": "AHREFS_FREE_MEASUREMENTS_2026-08-29.csv",
      "note": "Observed demand bin, not exact volume or a traffic forecast."
    }
  },
  "sources": {
    "hee_2025": {
      "title": "Household Energy Efficiency Statistics, detailed report 2025",
      "url": "https://www.gov.uk/government/statistics/household-energy-efficiency-statistics-detailed-report-2025",
      "publisher": "Department for Energy Security and Net Zero",
      "published": "2026-03-19",
      "licence": "Open Government Licence"
    },
    "gov_insulation": {
      "title": "Insulation: energy-efficient home guidance",
      "url": "https://cleanenergy.campaign.gov.uk/insulation/",
      "publisher": "UK Government"
    },
    "est_loft": {
      "title": "How to insulate a loft",
      "url": "https://energysavingtrust.org.uk/how-to-insulate-a-loft/",
      "publisher": "Energy Saving Trust"
    },
    "est_cavity": {
      "title": "Cavity wall insulation",
      "url": "https://energysavingtrust.org.uk/advice/cavity-wall-insulation/",
      "publisher": "Energy Saving Trust"
    },
    "competent_person": {
      "title": "Competent person schemes for cavity wall insulation",
      "url": "https://www.gov.uk/guidance/competent-person-scheme-current-schemes-and-how-schemes-are-authorised",
      "publisher": "UK Government"
    },
    "gbis": {
      "title": "Great British Insulation Scheme: homeowners and tenants",
      "url": "https://www.ofgem.gov.uk/environmental-and-social-schemes/great-british-insulation-scheme/homeowners-and-tenants",
      "publisher": "Ofgem",
      "note": "The page says the scheme was scheduled to end in April 2026. It is retained as historical funding context, not a current eligibility promise."
    },
    "vat": {
      "title": "Tax on shopping and services: energy-saving products",
      "url": "https://www.gov.uk/tax-on-shopping/energy-saving-products",
      "publisher": "UK Government",
      "note": "The calculator does not infer VAT treatment. Users enter the rate shown on the quote."
    },
    "wickes_100": {
      "title": "Knauf 100 mm Space bottom-layer loft roll",
      "url": "https://www.wickes.co.uk/Knauf-100mm-Insulation-Space-Bottom-Layer-Loft-Roll---11-08m2/p/109449",
      "publisher": "Wickes"
    },
    "wickes_170": {
      "title": "Knauf 170 mm Space top-up loft roll",
      "url": "https://www.wickes.co.uk/Knauf-Insulation-170mm-Space-Standard-Top-Up-Loft-Roll---6-47m2/p/109450",
      "publisher": "Wickes"
    },
    "wickes_200": {
      "title": "Knauf 200 mm Space super top-up loft roll",
      "url": "https://www.wickes.co.uk/Knauf-Insulation-200mm-Space-Super-Top-Up-Loft-Roll---5-61m2/p/109451",
      "publisher": "Wickes"
    }
  },
  "loft_product_snapshot": [
    {
      "source": "wickes_100",
      "product": "Knauf Space bottom layer loft roll",
      "thickness_mm": 100,
      "coverage_m2_pack": 11.08,
      "price_gbp": 37.0,
      "price_gbp_m2": 3.34,
      "checked_date": "2026-08-29"
    },
    {
      "source": "wickes_170",
      "product": "Knauf Space standard top-up loft roll",
      "thickness_mm": 170,
      "coverage_m2_pack": 6.47,
      "price_gbp": 38.0,
      "price_gbp_m2": 5.87,
      "checked_date": "2026-08-29"
    },
    {
      "source": "wickes_200",
      "product": "Knauf Space super top-up loft roll",
      "thickness_mm": 200,
      "coverage_m2_pack": 5.61,
      "price_gbp": 40.0,
      "price_gbp_m2": 7.12,
      "checked_date": "2026-08-29"
    }
  ],
  "housing_stock": [
    {
      "measure": "cavity_wall",
      "total_million": 21.8,
      "insulated_million": 15.4,
      "uncertain_million": 1.3,
      "easy_remaining_million": 3.7,
      "hard_or_unfillable_million": 1.3,
      "reference_period": "end-2025",
      "source": "hee_2025"
    },
    {
      "measure": "loft",
      "total_million": 26.3,
      "insulated_million": 17.7,
      "uncertain_million": 0.8,
      "easy_remaining_million": 5.5,
      "hard_or_unfillable_million": 2.2,
      "reference_period": "end-2025",
      "source": "hee_2025"
    }
  ],
  "reuse": "UK government housing-stock rows are published under the Open Government Licence. Retail price and pack facts remain attributed to their source and date; Inzonex does not relicense the source pages. Inzonex original calculations, field dictionary and charts may be reused with attribution."
}