Home Heat Pump Guide

Heat Pump Grant Calculator: Estimate Your Subsidy

Working out how much government funding you can get towards a heat pump should be simple — but with multiple schemes, varying eligibility criteria, and different rules across England, Scotland, and Wales, it rarely is. This guide acts as your grant calculator, walking you through exactly how much you could receive based on your property type, location, and circumstances.

We provide worked examples for seven different property scenarios so you can find the one closest to your situation and get a realistic estimate of your net cost after all available grants.

Which Grant Schemes Are Available?

Before we calculate, you need to know which schemes exist. The main options in 2026 are:

Boiler Upgrade Scheme (BUS) — England and Wales

  • Amount: £7,500 flat grant
  • Eligibility: Owner-occupiers and landlords replacing existing fossil fuel or electric heating
  • Requirements: Valid EPC, no outstanding loft/cavity insulation recommendations, MCS-certified installer
  • Application: Your installer applies on your behalf

Home Energy Scotland (HES) — Scotland

  • Grant amount: Up to £7,500
  • Loan amount: Up to £7,500 interest-free
  • Total potential support: Up to £15,000
  • Eligibility: Scottish homeowners, income and property-dependent for full amounts

ECO4 — Great Britain (Low Income)

  • Amount: Fully funded installation (worth £10,000+)
  • Eligibility: Households receiving certain means-tested benefits with low EPC ratings
  • Application: Through your energy supplier or an approved installer

Nest Scheme — Wales (Low Income)

  • Amount: Free or heavily subsidised installation
  • Eligibility: Welsh homeowners on low incomes or benefits

0% VAT — All UK

  • Saving: 20% of the installation cost (applied automatically)
  • This is not a grant but a tax relief that applies to all domestic heat pump installations

For a comprehensive overview of all schemes, see our complete guide to heat pump grants.

Worked Example 1: Three-Bedroom Semi, Gas Heating, England

This is the most common scenario in the UK.

  • Typical installation cost: £10,500 (8 kW ASHP, 200L cylinder, new controls)
  • VAT at 0%: Saves £2,100 compared to standard rate (already reflected in price)
  • BUS grant: £7,500
  • Net cost to homeowner: £3,000

For context, a new mid-range gas boiler for the same property would cost £3,000 to £3,500 — making the heat pump cost-neutral on installation, with a system that will last 20+ years versus 12-15 for the boiler.

Worked Example 2: Two-Bedroom Terrace, Gas Heating, England

  • Typical installation cost: £8,500 (5-6 kW ASHP, 170L cylinder)
  • BUS grant: £7,500
  • Net cost to homeowner: £1,000

For a smaller property, the grant covers the vast majority of the cost. This is arguably the best value scenario — you get a brand new, low-carbon heating system for roughly the cost of a new washing machine.

Worked Example 3: Four-Bedroom Detached, Oil Heating, England

  • Typical installation cost: £13,000 (12 kW ASHP, 300L cylinder, some radiator upgrades)
  • BUS grant: £7,500
  • Net cost to homeowner: £5,500

While the net cost is higher, oil-heated properties save the most on running costs — typically £300 to £500 per year. The payback on the £5,500 investment is around 11 to 18 years, and you eliminate the hassle and risk of oil tank ownership.

Worked Example 4: Three-Bedroom Semi, Gas Heating, Scotland

  • Typical installation cost: £10,500
  • Home Energy Scotland grant: Up to £7,500
  • Home Energy Scotland interest-free loan: Up to £3,000 (to cover remaining cost)
  • Net upfront cost to homeowner: Potentially £0

Scottish homeowners have access to the most generous support package in the UK. Between the grant and the interest-free loan, many installations can be funded entirely without any upfront cash outlay. The loan is repaid over time but carries no interest.

Worked Example 5: Rural Cottage, LPG Heating, Wales

  • Typical installation cost: £11,000 (8 kW ASHP, cylinder, flue removal)
  • BUS grant: £7,500
  • Net cost to homeowner: £3,500

Welsh homeowners benefit from both the BUS grant and access to the Nest scheme if on a low income. For LPG users, the annual running cost saving of £400 to £700 means the £3,500 net cost is recovered within five to nine years. See our full LPG comparison.

Worked Example 6: Low-Income Household on Benefits, England

  • Typical installation cost: £10,500
  • ECO4 funding: Up to 100% of cost
  • Net cost to homeowner: £0

If you receive Universal Credit, Pension Credit, Child Tax Credit, or certain other means-tested benefits, and your property has an EPC rating of D, E, F, or G, you may qualify for a fully funded heat pump through ECO4. Your energy supplier or an approved installer can assess your eligibility.

Worked Example 7: Five-Bedroom Detached, Ground Source Heat Pump, England

  • Typical installation cost: £24,000 (ground source system with borehole)
  • BUS grant: £7,500
  • Net cost to homeowner: £16,500

For large properties with ground source systems, the £7,500 grant covers a smaller proportion of the total cost. However, ground source heat pumps achieve higher efficiencies (COP 4.0+) and have lifespans of 25+ years, making the long-term economics strong despite the higher upfront investment.

How to Calculate Your Own Net Cost

Follow these steps:

  1. Get quotes: Request quotes from MCS-certified installers — get at least three
  2. Confirm VAT: Ensure quotes are at 0% VAT (check this is stated on the quote)
  3. Determine your grant: In England/Wales, deduct £7,500 (BUS). In Scotland, check Home Energy Scotland for your specific grant amount.
  4. Check additional funding: If you receive means-tested benefits, check ECO4 eligibility with your energy supplier
  5. Calculate net cost: Total quote minus total grants = your cost

For a quick estimate before getting quotes, use our heat pump calculator which estimates costs based on your property details.

Factors That Affect Your Installation Cost

The total cost (before grants) depends on several factors:

  • Property size and heat demand: Larger homes need bigger heat pumps, larger cylinders, and potentially more radiator upgrades
  • Current heating system: Replacing a system boiler with existing radiators is cheaper than a full system change from a combi boiler (which requires adding a cylinder)
  • Insulation level: Better-insulated homes can use smaller, cheaper heat pumps. Check your suitability.
  • Radiator changes: Some properties need larger radiators to work effectively at lower flow temperatures
  • Ground conditions (for GSHP): Borehole drilling costs vary by geology
  • Location: Labour costs vary across the UK, with London and the South East typically being more expensive

Maximising Your Grant Value

Tips to get the most from the available funding:

  • Get multiple quotes: Prices vary significantly between installers. Three quotes minimum.
  • Do insulation first: Improving insulation before installing a heat pump means you can fit a smaller, cheaper unit — maximising the proportion covered by the grant
  • Check Scottish loan options: If in Scotland, the interest-free loan can eliminate all upfront cost
  • Ask about ECO4: Even if you think you might not qualify, it is worth checking. Eligibility has expanded in recent years.
  • Time your installation: Spring and summer tend to have shorter wait times and occasionally better pricing as installer demand is lower

Frequently Asked Questions

Is the £7,500 grant the same for all property sizes?

Yes. The BUS grant is a flat £7,500 regardless of property size or installation cost. This means it covers a larger proportion of the cost for smaller, cheaper installations.

Can I get more than one grant?

You cannot combine BUS with ECO4 for the same installation. You can benefit from 0% VAT alongside any grant. In Scotland, you can combine the HES grant with the interest-free loan.

Does the grant cover radiator upgrades?

The BUS grant covers the heat pump system. If your installer includes radiator upgrades as part of the heat pump installation package (which many do), the grant applies to the whole invoice.

What if I need insulation work first?

Insulation work is not covered by the BUS grant — it is a separate cost. However, some local authority schemes and ECO4 can fund insulation improvements. Address insulation first, then apply for the heat pump grant.

How quickly can I get the grant?

The BUS application typically takes two to three weeks for Ofgem to approve. Combined with getting quotes and scheduling installation, most homeowners go from first enquiry to completed installation in six to twelve weeks.

Is there a deadline to apply?

The BUS is funded until March 2028. However, there is an annual budget cap, and if demand exceeds supply in any year, the scheme could close early. Applying sooner rather than later avoids this risk.