Can I Combine UK Government Grants with Mortgage Finance for Home Energy Upgrades?
Yes, combining UK government grants like BUS or ECO4 with mortgage finance is effective for funding home energy improvements.
By CarbonFree Team. Published 2025-10-22. Last updated 2026-10-21.
Yes, it is both possible and increasingly common for UK homeowners to combine government energy grants with mortgage finance to fund home energy upgrades. This approach allows homeowners to significantly reduce the upfront cost of improvements while spreading the remaining balance over a longer term at competitive interest rates.
What UK Government Energy Grants Are Available?
The UK government offers several schemes to support homeowners in making their properties more energy-efficient. These grants typically target specific technologies or households.
Boiler Upgrade Scheme (BUS)
The Boiler Upgrade Scheme (BUS) is available in England and Wales. It offers grants of up to £7,500 towards the cost of installing air source or ground source heat pumps. The grant is paid directly to the installer, reducing the final invoice to the homeowner.
ECO4 Scheme
The Energy Company Obligation (ECO4) scheme targets households with lower incomes or those in fuel poverty. It provides funding for a range of energy-saving measures, including insulation, heating system upgrades, and renewable energy installations. Funding through ECO4 is delivered by approved installers.
These grants are designed to lower the initial financial barrier to adopting greener technologies, making it easier to combine with other forms of finance.
How Can Mortgages Fund the Remaining Cost?
Even with grants, many energy upgrades still require a significant investment, often ranging from £5,000 to £15,000. Homeowners can finance this remaining balance through several mortgage-related options:
- Remortgaging: Incorporating the cost into a new mortgage deal.
- Secured Home Improvement Loan: A loan secured against your property.
- Further Advance: An additional loan from your existing mortgage lender.
Using mortgage finance allows homeowners to spread the cost over extended periods, often 20-30 years, at mortgage-level interest rates. These rates are typically much lower than those offered by personal loans or installer-specific finance. For example, a £12,000 heat pump installation, reduced to £4,500 after a BUS grant, might add only £25–£30 to monthly mortgage payments when financed at 4.5% over 25 years.
Why Combine Grants with Mortgage Finance?
Combining these funding streams offers several advantages for homeowners:
- Lower Upfront Costs: Grants directly reduce the initial expenditure.
- Affordable Repayments: Mortgage-level interest rates and longer terms make repayments more manageable.
- Increased Property Value: Homes with higher Energy Performance Certificate (EPC) ratings (A-C) can see a 5-10% increase in value.
- Improved Affordability Assessments: Under UK mortgage regulations (MCOB 11), lenders may consider potential energy bill savings when assessing a borrower's ability to afford repayments.
- Reduced Energy Bills: Upgraded homes consume less energy, leading to lower utility costs.
How to Successfully Combine Finance Options
To combine grants and mortgage finance effectively, follow these steps:
- Grant Application: Apply for the relevant grant (e.g., BUS) and secure a confirmation letter or voucher number.
- Installer Quotes: Obtain detailed quotes from certified installers. Ensure the quotes clearly show the total cost and the cost after the grant has been applied.
- Lender Consultation: Present these figures to your mortgage adviser or lender. They can assess how the remaining balance can be incorporated into your mortgage or a secured loan.
- Energy Performance Data: Provide your EPC or modelled energy savings data. Tools like the CarbonFree Navigator can help you predict potential savings.
- Mortgage Arrangement: Proceed with the remortgage or loan once your lender confirms affordability and all figures are agreed upon.
Typical Upgrade Bundles and Financing Examples
Homeowners often combine different energy efficiency measures. Here's a look at common upgrades, potential grants, and typical finance needs:
| Upgrade | Potential Grant | Typical Extra Finance Needed | Annual Saving (approx.) |
|---|---|---|---|
| Air-source heat pump | £7,500 (BUS) | £4,000–£8,000 | £400–£600 |
| Solar PV + battery | N/A | £6,000–£10,000 | £700–£1,200 |
| Insulation + heat pump (ECO4) | Full funding possible | £0–£2,000 | £600–£900 |
*Note: "N/A" for solar PV currently indicates no direct government grant equivalent to BUS, but other incentive schemes or local grants may exist.*
For personalised calculations and bespoke advice on financing your green home improvements, CarbonFree offers expert consultancy and finance solutions. Our Navigator Lite tool can also provide an initial estimate of your potential savings.
Key Takeaway
Combining government grants with mortgage finance presents a powerful and accessible pathway for UK homeowners to undertake significant home energy efficiency upgrades. Grants reduce the initial burden, while mortgage finance makes the remaining cost affordable over the long term, enabling homeowners to invest in a greener, more valuable, and more cost-efficient home today.
Related Resources
- Explore Our Consultancy Services
- Understanding Home Energy Finance
- CarbonFree Navigator Lite: Estimate Your Savings
- Partner with CarbonFree
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