Fund emergency home energy upgrades: note

Central fiscal result

+£5.0bn - Net fiscal impact in 2028-29

Low case: +£3.0bn. High case: +£11.0bn. Positive numbers are fiscal costs or borrowing pressure. Negative numbers are Exchequer savings or receipts.

Scenario and baseline

• Models fund emergency home energy upgrades 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 +£5.0bn 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: +£5.8bn
• Tax and receipt offsets: -£0.4bn
• Administration and evaluation: +£0.1bn
• Behavioural and pass-through effects: -£0.5bn

Central net impact: +£5.0bn 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: +£0.5bn. Phased implementation and take-up.
• 2027-28: +£2.8bn. Phased implementation and take-up.
• 2028-29: +£5.0bn. Phased implementation and take-up.
• 2029-30: +£5.0bn. Phased implementation and take-up.

Main source groups

• Acemoglu, Aghion, Bursztyn and Hemous, "The Environment and Directed Technical Change" (American Economic Review, 2012): Climate policy can redirect innovation, but transition dynamics and path dependence matter; relevant to green investment and clean-power policy.
• Andersson, "Carbon Taxes and CO2 Emissions" (American Economic Journal: Economic Policy, 2019): Sweden’s carbon tax reduced emissions while maintaining economic growth, but institutional context mattered; supports carbon-pricing benefits with design caveats.
• Liberal Democrats, "Funding a Fair Deal: Liberal Democrat Manifesto Costings" (2024): Party costings give 2028-29 spending, revenue and investment figures; used as starting anchors, not official costings.
• Liberal Democrats, "For a Fair Deal: Liberal Democrat Manifesto 2024" (2024): The manifesto gives announced policy detail across health, care, housing, taxes and climate; used to define the policy scenarios.