If your home has received an E, F or G rating, you’re not alone. Many UK properties — particularly older homes — struggle to achieve higher EPC bands.

Understanding why your property scored low is the first step toward improving it.

EPCs are regulated under guidance set by the UK Government and calculated using the Standard Assessment Procedure (SAP).

Here are the most common reasons homes receive a low EPC rating.

1. Poor Loft Insulation

Heat rises — and without proper loft insulation, your home loses significant warmth.

Common issues:

  • Less than recommended 270mm insulation

  • No insulation at all

  • Compressed or damaged insulation

This alone can significantly reduce your EPC score.

2. Solid Walls Without Insulation

Older homes (pre-1930s) often have solid brick walls rather than cavity walls.

Without:

  • Internal wall insulation

  • External wall insulation

heat escapes easily, lowering efficiency.

Solid wall properties often struggle to achieve higher bands without upgrades.

3. Old or Inefficient Boiler

Heating systems heavily influence EPC scores.

Problems include:

  • Non-condensing boilers

  • Boilers over 15 years old

  • Poor maintenance

  • Lack of heating controls

Upgrading to a modern condensing boiler can substantially improve your rating.

Book reassessment after improvements:
https://epcrate.co.uk/booking/

4. Lack of Heating Controls

Missing controls such as:

  • Programmable thermostats

  • Thermostatic radiator valves (TRVs)

  • Smart heating systems

can reduce efficiency scoring.

Even if the boiler is modern, poor controls can limit your EPC band.

5. Single Glazing

Single-glazed windows allow heat to escape quickly.

Homes with:

  • Original timber frames

  • Metal-framed windows

  • Draughty fittings

often lose EPC points compared to double-glazed properties.

6. Inefficient Lighting

Properties still using:

  • Halogen bulbs

  • Incandescent lighting

lose easy EPC points.

Switching to LED lighting is one of the simplest upgrades.

7. Electric-Only Heating (Without Heat Pump)

Electric panel heaters or storage heaters can result in lower EPC scores due to higher assumed energy costs — unless paired with efficient heat pump systems.

8. No Renewable Energy Systems

Homes without:

  • Solar panels

  • Solar water heating

  • Heat pumps

may score lower compared to properties with renewable technology.

While not mandatory, renewables can boost ratings significantly.

9. Older Property Construction

Older properties often have:

  • Less airtight construction

  • Poor insulation standards

  • Outdated building materials

Without upgrades, these homes naturally receive lower EPC bands.

10. Incorrect or Missing Information

Sometimes a low rating occurs because:

  • Improvements weren’t visible during inspection

  • Documentation wasn’t provided

  • Insulation couldn’t be verified

Providing evidence (e.g., insulation certificates, boiler installation records) can improve accuracy.

Consult certified assessors:
https://epcrate.co.uk/services-epc-assessors-london/

Check pricing here:
https://epcrate.co.uk/pricing/

Meet our company:
https://epcrate.co.uk/about-us-epc-company-london/

Does a Low EPC Affect Selling?

Yes — while there is no minimum rating required to sell in 2026, low ratings can:

  • Reduce buyer interest

  • Trigger negotiations

  • Raise mortgage concerns

Rental properties must also comply with the Minimum Energy Efficiency Standards (MEES), requiring EPC E or above.

Final Thoughts

Most low EPC ratings result from:

✔ Poor insulation
✔ Old heating systems
✔ Inefficient glazing
✔ Lack of controls
✔ Outdated lighting

The good news? Many of these issues are fixable — often without major renovation.

Improving even one or two key areas can sometimes move your home up a full band.

Office: 150–160 City Road, London, EC1V 2NX
Phone: 020 3488 4142
Email: info@epcrate.co.uk