An Energy Performance Certificate (EPC) gives your property a rating from A (most efficient) to G (least efficient), indicating how energy-efficient your home is. Understanding how different upgrades affect these bands is essential for homeowners and landlords looking to improve comfort, reduce energy bills, and maximise property value.

Our expert EPC Assessors in London regularly advise on the most effective upgrades to move properties up the EPC scale:
👉 https://epcrate.co.uk/services-epc-assessors-london/

1. EPC Bands Explained

EPC ratings are calculated based on:

  • Building fabric: walls, roof, floors, insulation

  • Windows and doors: type, glazing, draughts

  • Heating systems: boilers, radiators, heat pumps

  • Heating controls: thermostats, TRVs, zoning

  • Lighting: energy-efficient fixtures

  • Renewable systems: solar panels, heat pumps, or other renewable tech

Each element contributes to the overall rating, which is then categorised into a band:

  • Band A: Excellent efficiency

  • Band B: Very good

  • Band C: Good

  • Band D: Average

  • Band E: Below average

  • Band F: Poor

  • Band G: Very poor

2. How Upgrades Influence EPC Bands

a) Insulation Upgrades

  • Loft insulation: Increasing depth improves heat retention.

  • Cavity wall insulation: Fills gaps in walls, reducing heat loss.

  • Solid wall insulation: External or internal insulation can make a big difference in older properties.

Impact: Typically moves properties up 1–2 bands if other elements are standard.

b) Heating System Improvements

  • Replacing an old boiler with a high-efficiency condensing boiler

  • Installing a heat pump or renewable heating

  • Servicing and optimising existing systems

Impact: Strong effect on EPC scores, often moving properties from D/E to C/B.

👉 Learn more about heating upgrades:
https://epcrate.co.uk/services-epc-assessors-london/

c) Heating Controls

  • Thermostatic Radiator Valves (TRVs)

  • Programmable room thermostats

  • Zoned heating systems

  • Smart thermostats

Impact: Small upgrades with a surprisingly high influence on EPC ratings, particularly in combination with an efficient boiler.

d) Draught-Proofing

Sealing gaps around doors, windows, loft hatches, and chimneys reduces energy loss.

Impact: Improves building fabric efficiency; often sufficient to push a property up one EPC band when combined with insulation.

e) Windows and Glazing

  • Replacing single glazing with double or triple glazing

  • Ensuring frames are sealed and draught-free

Impact: More noticeable in older properties; can improve both thermal efficiency and EPC band.

f) Lighting

  • Upgrading all permanent fixtures to LED or low-energy bulbs

Impact: Small but measurable contribution to EPC points; helps reach higher bands in combination with other upgrades.

g) Renewable Energy Systems

  • Solar PV panels

  • Solar water heating

  • Air or ground-source heat pumps

Impact: Can significantly boost EPC scores, especially when combined with efficiency improvements.

3. Strategic Upgrade Planning

Not all upgrades have the same effect for every property. Assessing where your property currently scores poorly allows targeted improvements that maximise EPC points per pound spent.

  • Older homes: Focus on insulation, draught-proofing, and efficient heating

  • Modern homes: Heating controls, lighting, and renewable additions may deliver bigger gains

  • Landlords: Focus on cost-effective measures to meet minimum EPC requirements (Band E or above)

4. The Importance of Documentation

Even the best upgrades won’t improve your EPC if they cannot be verified:

  • Installation certificates

  • Invoices for insulation or heating upgrades

  • Manufacturer specifications

  • Photos of work completed

Proper documentation ensures assessors can credit your improvements, helping you achieve the higher band you deserve.

5. When to Schedule a Re-Assessment

After completing upgrades:

  1. Gather all relevant documentation

  2. Ensure all systems are visible and operational

  3. Book an EPC re-assessment to reflect improvements

👉 Schedule your EPC assessment here:
https://epcrate.co.uk/booking/

6. Key Takeaways

  • EPC bands range from A (most efficient) to G (least efficient)

  • Insulation, heating systems, controls, draught-proofing, windows, lighting, and renewable energy all influence bands

  • Small, targeted improvements often provide high EPC points per cost

  • Proper documentation ensures all improvements are credited

  • Strategic planning helps homeowners and landlords maximise energy efficiency, compliance, and property value