PolicyLens

Methodology note

Expand the Warm Homes Plan: note

Models expand the warm homes plan in 2028-29. The estimate is illustrative and excludes wider package interactions.

View main policy page: Expand the Warm Homes Plan

Central fiscal result

+GBP 3.0bn - Net fiscal impact in 2028-29

Low case: +GBP 1.5bn. High case: +GBP 6.0bn. Positive numbers are fiscal costs or borrowing pressure. Negative numbers are Exchequer savings or receipts.

Scenario and baseline

  • Models expand the warm homes plan by 2028-29.
  • Baseline is current policy or published departmental plans.
  • Central case uses published party or official anchors where available.
  • Wider manifesto interactions are excluded unless stated.

Affected population

  • Affected units are people, firms, households or providers depending on policy.
  • Direct exposure follows the manifesto or government target group.
  • Indirect exposure includes suppliers, workers, consumers and taxpayers.
  • Weakest counts are widened in the low and high cases.

Gross impact

  • Published anchor or scenario central is +GBP 3.0bn in 2028-29.
  • Gross costs or receipts are adjusted for behaviour and delivery risk.
  • Tax, benefit or procurement offsets are separated in the fiscal build-up.
  • The range is deliberately wider where implementation detail is thin.

Fiscal build-up, central case

  • Gross programme or delivery cost: +GBP 3.4bn
  • Tax and receipt offsets: -GBP 0.2bn
  • Administration and evaluation: +GBP 0.1bn
  • Behavioural and pass-through effects: -GBP 0.3bn

Central net impact: +GBP 3.0bn in 2028-29.

Behaviour and pass-through

  • Low case assumes stronger delivery or receipts than central.
  • Central case applies moderate behavioural leakage and pass-through.
  • High case allows weaker delivery, larger take-up or higher costs.
  • Output effects follow incidence, capacity and investment channels.
  • Distributional gains do not automatically imply GDP gains.

Phasing

  • 2026-27: +GBP 0.3bn. Phased implementation and take-up.
  • 2027-28: +GBP 1.7bn. Phased implementation and take-up.
  • 2028-29: +GBP 3.0bn. Phased implementation and take-up.
  • 2029-30: +GBP 3.0bn. Phased implementation and take-up.

Main source groups

  • S1: Department for Energy Security and Net Zero: source for scenario or evidence.
  • S2: Labour Party: source for scenario or evidence.
  • S3: HM Treasury: source for scenario or evidence.
  • S4: American Economic Journal: Economic Policy: source for scenario or evidence.
  • S5: NBER: source for scenario or evidence.