Best Home Improvements to Improve Your EPC Rating in 2026 — Ranked by Impact and Cost

Why Your EPC Rating Matters in 2026

An Energy Performance Certificate (EPC) rates your property's energy efficiency on a scale from A (most efficient) to G (least efficient). In 2026, EPC ratings matter more than ever. Landlords in England and Wales must already meet a minimum EPC E under the Minimum Energy Efficiency Standards (MEES). The government has consulted on requiring all new tenancies to achieve a minimum EPC C by 2030 — this is not yet law, but landlords should be planning for it now.

For owner-occupiers, a better EPC means lower energy bills, increased property value, and access to green mortgage products that offer preferential rates to energy-efficient homes.

How EPC Ratings Are Calculated

EPCs are produced by accredited Domestic Energy Assessors (DEAs) using the Standard Assessment Procedure (SAP), a government-approved methodology. SAP scores run from 1 to 100+. A higher SAP score equates to a better EPC band:

Most UK homes currently sit in bands D or E. Moving from E to C typically requires a SAP improvement of 15–30 points depending on the property.

Improvements Ranked by EPC Impact

1. Loft Insulation — High Impact, Low Cost

Uninsulated lofts account for around 25% of heat loss in a typical semi-detached home. Installing 270mm of mineral wool insulation typically adds 4–8 SAP points and costs £300–£600 for a standard semi, often less if you qualify for ECO4 or the Great British Insulation Scheme (GBIS). Payback is typically 2–4 years.

2. Cavity Wall Insulation — High Impact for Post-1930 Homes

Properties built between roughly 1930 and 1990 usually have a cavity between the inner and outer brick leaf. Injecting insulation beads or foam into this cavity can add 5–10 SAP points and costs £500–£1,500. It is one of the most cost-effective improvements available. Pre-1930 or solid-walled properties require a different approach (see the solid wall insulation guide).

3. Air Source Heat Pump — Transformational but Higher Cost

Replacing a gas boiler with an air source heat pump (ASHP) can add 10–20 SAP points in properties with good fabric insulation. The Boiler Upgrade Scheme (BUS) currently offers a £7,500 grant towards the cost of an ASHP or ground source heat pump (GSHP). Total installed cost after the grant is typically £5,000–£10,000. The EPC impact is largest in well-insulated properties.

4. Solar Photovoltaic Panels — Strong EPC Boost and Bill Savings

A 3.5 kWp solar PV system can add 10–15 SAP points, often enough to move a D-rated home to a C. Average installed cost is £5,000–£8,000 in 2026. You can also export surplus electricity under the Smart Export Guarantee (SEG).

5. Double Glazing — Moderate Impact

Replacing single glazing with A-rated double glazing adds 2–5 SAP points and significantly improves comfort. Cost per window is typically £400–£800. Secondary glazing (a separate inner pane) costs less and still delivers meaningful improvement where full replacement is not possible.

6. Boiler Replacement

An older boiler (pre-2010) running at 70–75% efficiency is a significant drag on your EPC score. Replacing it with a modern A-rated condensing boiler (90%+ efficiency) can add 3–7 SAP points at a cost of £2,000–£4,000. Note that heat pumps score more favourably under SAP than even the best gas boilers.

7. Floor Insulation

Insulating an uninsulated suspended timber ground floor adds 1–4 SAP points at a cost of £800–£2,000. Solid concrete floors are harder and more expensive to insulate effectively.

8. Heating Controls and Smart Thermostats

Adding a programmer, room thermostat, and thermostatic radiator valves (TRVs) where missing can add 1–3 SAP points at very low cost — sometimes under £300 in materials. Smart thermostats such as Nest or Hive cost £150–£250 installed and improve real-world efficiency, though their SAP impact is modest.

Strategy: What to Do First

If budget is limited, tackle measures in this order: loft insulation → cavity wall insulation (if applicable) → heating controls → boiler replacement → solar PV → heat pump. This order maximises SAP gain per pound spent for most UK properties.

Use our [EPC Improvement Calculator](/epc-improvement-calculator) to model the specific impact each measure would have on your property's EPC rating and estimated running costs.

Available Grants in 2026

• **ECO4**: Free insulation, heating, and glazing for low-income households — administered through energy suppliers
• **Great British Insulation Scheme (GBIS)**: Free or subsidised insulation for properties in Council Tax bands A–D and EPC D–G
• **Boiler Upgrade Scheme (BUS)**: £7,500 grant for air source and ground source heat pumps
• **Local Authority Flex (LA Flex)**: Additional funding routed through local councils, often with wider eligibility criteria

Always check current eligibility before assuming you qualify — scheme rules and funding levels can change.