Correct the Warm Home Discount docs page (#502)

changelog.d/502-warm-home-discount-corrections.changed.md

@@ -0,0 +1 @@
+Corrected the Warm Home Discount plan (docs/book/programs/gov/ofgem/warm-home-discount-plan.md): the April-to-March scheme year, the Scottish core group under Schedule 1 to SI 2026/488, the pre-2022 rebate amounts, the 2025-26 qualifying benefits, the helpline route and the ESA take-up caveat.

docs/book/programs/gov/ofgem/warm-home-discount-plan.md

@@ -3,7 +3,9 @@
 ```{warning}
 **Not yet modelled.** The Warm Home Discount (WHD) is a £150 rebate off
 a household's electricity bill each winter, paid by energy suppliers
-under schemes that Ofgem administers. PolicyEngine UK doesn't model it.
+under schemes that Ofgem administers. PolicyEngine UK doesn't model it;
+draft [#2504](https://github.com/PolicyEngine/policyengine-uk/pull/2504)
+implements Phase 1 below.
 This page sets out the proposed scope, tracked in
 [#502](https://github.com/PolicyEngine/policyengine-uk/issues/502).
 Updated October 2026: in England and Wales eligibility is now based on
@@ -21,13 +23,19 @@ They replace the
 [2022 Regulations](https://www.legislation.gov.uk/uksi/2022/772/contents)
 (SI 2022/772), which applied to both England and Wales.
 
-Under the 2022 Regulations, the means-tested group had to pass a
-"high cost to heat" test based on property data. For winter 2025-26
-that test was removed, so every household on a qualifying means-tested
+Under the eligibility statements made under the 2022 Regulations, the
+means-tested group (Core Group 2) had to pass a "high cost to heat" test
+based on property data. For winter 2025-26 the eligibility statement
+removed that test, so every household on a qualifying means-tested
 benefit became eligible. The government estimated this would bring
-2.7 million more households into the scheme, taking it to more than
-6 million households in Great Britain
-([government response, June 2025](https://assets.publishing.service.gov.uk/media/6852e6e9679778c74ec15e82/expanding-the-warm-home-discount-scheme-2025-to-2026-government-response.pdf)).
+2.7 million more households into the scheme
+([government response, June 2025](https://assets.publishing.service.gov.uk/media/6852e6e9679778c74ec15e82/expanding-the-warm-home-discount-scheme-2025-to-2026-government-response.pdf)),
+taking it to around 6.1 million households in Great Britain
+([impact assessment](https://assets.publishing.service.gov.uk/media/68529908ff16d05c5e6aa678/expanding-the-warm-home-discount-scheme-2025-to-2026-impact-assessment.pdf)).
+For winter 2025-26 (qualifying date 24 August 2025) the qualifying
+benefits also included income-based Jobseeker's Allowance and Income
+Support, with Pension Credit Guarantee Credit in a separate core group
+([eligibility statement, 2025 to 2026](https://www.gov.uk/government/publications/warm-home-discount-eligibility-statement-england-and-wales-2025-to-2026-scheme-year/warm-home-discount-eligibility-statement-england-and-wales-2025-to-2026)).
 
 For winter 2026-27, GOV.UK
 ([eligibility in England and Wales](https://www.gov.uk/the-warm-home-discount-scheme/if-you-live-in-england-and-wales))
@@ -41,7 +49,9 @@ their partner gets one of:
 - income-related Employment and Support Allowance;
 - Pension Credit.
 
-The rebate is applied automatically.
+Most eligible households get the rebate automatically through data
+matching; the rest are sent a letter and must call the helpline by
+26 February 2027 to confirm their details.
 
 ### Scotland
 
@@ -53,12 +63,18 @@ The scheme runs under separate Scottish regulations.
 (SI 2022/1073). Both 2026 Regulations set the rebate at £150. For winter 2026-27
 ([eligibility in Scotland](https://www.gov.uk/the-warm-home-discount-scheme/if-you-live-in-scotland)):
 
-- **Core group, automatic:** Pension Credit; Universal Credit with an
-  extra amount for a disability or health condition; income-related ESA
-  with a disability or pensioner premium; or a Support for Mortgage
-  Interest loan with one of those premiums. Also people responsible for
-  a child under 5 who are unemployed and on Universal Credit or
-  income-related ESA, or have a Support for Mortgage Interest loan.
+- **Core group, automatic.** Under Schedule 1 to the Regulations:
+  anyone on Pension Credit; Universal Credit claimants with the disabled
+  child addition, or who are not in work and have a child under 5 or
+  limited capability for work (with or without work-related activity);
+  income-related ESA claimants with a child under 5, a pensioner, severe
+  disability or enhanced disability premium, or limited capability for
+  work or work-related activity; Income Support or income-based JSA
+  claimants with a child under 5 or a pensioner, higher pensioner,
+  disability, severe disability, enhanced disability or disabled child
+  premium; and people receiving loans for mortgage interest through
+  Pension Credit, or through one of those legacy benefits with a child
+  under 5 or a qualifying premium. GOV.UK's summary is narrower.
 - **Broader group, by application** to the energy supplier, which can
   set its own extra criteria.
 
@@ -76,22 +92,29 @@ extends to Great Britain only.
 Now a rule on benefit receipt:
 
 - Parameter `gov.ofgem.warm_home_discount.amount`: £150, the
-  "prescribed rebate" in both sets of 2026 Regulations (£140 before
-  winter 2022-23).
-- Parameter listing the qualifying benefits, so a reform can widen or
-  narrow the list.
+  "prescribed rebate" in both sets of 2026 Regulations (£150 since
+  winter 2022-23; under the Warm Home Discount Regulations 2011 it was
+  £140 from 2014-15 to 2021-22, after £120, £130 and £135 in the first
+  three scheme years).
+- Parameter listing the qualifying benefits by scheme year, since the
+  2025-26 and 2026-27 lists differ, so a reform can widen or narrow the
+  list.
 - Variable `warm_home_discount` (Household, YEAR): the amount if the
   household is in England or Wales and any benefit unit receives a
   qualifying benefit. Read receipt from the modelled benefits, for
   example `universal_credit`, `housing_benefit`, `esa_income` and
-  `pension_credit`, so that take-up carries through.
-- No separate take-up flag, since the rebate is paid without a claim.
+  `pension_credit`, so that take-up carries through (`esa_income` is
+  reported receipt, screened by capital and work tests).
+- No separate take-up flag, since most rebates are paid through data
+  matching without a claim (a minority must phone the helpline).
 
 ### Phase 2: Scotland core group
 
-The core group can be built from the same benefit variables plus the
-Universal Credit disability elements, the ESA premiums and the age of
-the youngest child.
+The core group can be built from the same benefit variables plus
+Universal Credit's disabled child and limited capability for work
+assessments, whether the claimant is in work, whether there is a child
+under 5, and legacy-benefit premiums. ESA's pensioner premium and loans
+for mortgage interest have no variables yet.
 
 ### Phase 3: Scotland broader group
 
@@ -100,8 +123,8 @@ published recipient numbers for Scotland, on top of the eligible group.
 
 ## Data and calibration
 
-- Ofgem's [Warm Home Discount pages](https://www.ofgem.gov.uk/environmental-and-social-schemes/warm-home-discount-whd):
-  recipients and spend by group and country.
+- Ofgem's [Warm Home Discount reports and data](https://www.ofgem.gov.uk/environmental-and-social-schemes/warm-home-discount-whd/warm-home-discount-whd-reports-and-data)
+  and annual reports: recipients and spend by group and country.
 - DWP benefit caseloads, already used to calibrate the qualifying
   benefits.
 - The 2025-26 impact assessment and government response give the
@@ -110,10 +133,11 @@ published recipient numbers for Scotland, on top of the eligible group.
 
 ## Open questions
 
-- **Timing.** The scheme year runs from October to March, with the
-  qualifying date in August. A model year (April to March) contains one
-  winter's rebate, so pay the rebate in the year that contains the
-  winter.
+- **Timing.** The scheme year runs from April to March, but rebates are
+  paid in the winter: letters go out from late October and suppliers
+  apply the discount by 31 March, with the qualifying date in August. A
+  model year (6 April to 5 April) contains one scheme year's rebate, so
+  pay it in the model year that contains the winter.
 - **Who counts as the household.** The rebate attaches to an
   electricity account. In multi-benefit-unit households, decide whether
   one qualifying benefit unit is enough (simplest, and likely right for
@@ -130,7 +154,9 @@ published recipient numbers for Scotland, on top of the eligible group.
 - [The Warm Home Discount (England and Wales) Regulations 2022 (SI 2022/772)](https://www.legislation.gov.uk/uksi/2022/772/contents).
 - [The Warm Home Discount (Scotland) Regulations 2026 (SI 2026/488)](https://www.legislation.gov.uk/uksi/2026/488/contents).
 - [The Warm Home Discount (Scotland) Regulations 2022 (SI 2022/1073)](https://www.legislation.gov.uk/uksi/2022/1073/contents).
-- DESNZ, [Expanding the Warm Home Discount scheme, 2025 to 2026: government response](https://assets.publishing.service.gov.uk/media/6852e6e9679778c74ec15e82/expanding-the-warm-home-discount-scheme-2025-to-2026-government-response.pdf).
+- DESNZ, [Expanding the Warm Home Discount scheme, 2025 to 2026: government response](https://assets.publishing.service.gov.uk/media/6852e6e9679778c74ec15e82/expanding-the-warm-home-discount-scheme-2025-to-2026-government-response.pdf) and [impact assessment](https://assets.publishing.service.gov.uk/media/68529908ff16d05c5e6aa678/expanding-the-warm-home-discount-scheme-2025-to-2026-impact-assessment.pdf).
+- DESNZ, [Warm Home Discount eligibility statement, England and Wales, 2025 to 2026](https://www.gov.uk/government/publications/warm-home-discount-eligibility-statement-england-and-wales-2025-to-2026-scheme-year/warm-home-discount-eligibility-statement-england-and-wales-2025-to-2026).
+- [The Warm Home Discount Regulations 2011 (SI 2011/1033)](https://www.legislation.gov.uk/uksi/2011/1033/regulation/2): earlier rebate amounts.
 - GOV.UK, [Warm Home Discount Scheme](https://www.gov.uk/the-warm-home-discount-scheme).
-- Ofgem, [Warm Home Discount scheme pages and reports](https://www.ofgem.gov.uk/environmental-and-social-schemes/warm-home-discount-whd).
+- Ofgem, [Warm Home Discount scheme pages](https://www.ofgem.gov.uk/environmental-and-social-schemes/warm-home-discount-whd) and [reports and data](https://www.ofgem.gov.uk/environmental-and-social-schemes/warm-home-discount-whd/warm-home-discount-whd-reports-and-data).
 - Issue: [#502](https://github.com/PolicyEngine/policyengine-uk/issues/502).