Read the latest news & industry developments

Read the latest news & industry developments



How to Improve Your EPC Rating

Hugh Franklin

28th November 2023


Air Tightness

For builders, property developers, and homeowners, improving a property’s Energy Performance Certificate (EPC) rating is essential. Not only does this allow the home to adhere to the UK’s building regulations, but it also reduces running costs and improves energy efficiency for any current or future occupier. Furthermore, higher EPC ratings directly correlate to higher property values – the more energy-efficient a home is, the more it is worth.

What is an EPC?


An Energy Performance Certificate (EPC) is a document that shows a property’s energy performance. It also offers recommendations on boosting a property’s energy efficiency. EPC ratings are graded from A (most efficient) to G (least efficient) and are required for properties being sold or rented in the UK. 


What Goes Into an EPC Rating?


An EPC rating is a reflection of a property’s energy efficiency, gauged based on various factors:

  • Insulation: Effective insulation in walls, roofs, and floors significantly curtail heat loss.
  • Heating Systems: The efficiency and modernity of heating systems and controls are key determinants.
  • Ventilation: Apt ventilation systems ensure a balanced indoor air quality while aiding in energy conservation. You can read more about this in our article “Part F Building Regulations
  • Airtightness: Draughts in buildings are the largest area of energy loss in UK homes – EPCs for both new-build and existing homes will reward less leaky homes with an improved score.
  • Renewable Energy Resources: Incorporation of renewable energy sources like solar panels or wind turbines.
  • Windows and Doors: The energy efficiency attributes of windows and doors, including their U-values and quality.
  • Lighting: Employing energy-saving bulbs and efficient lighting systems play a part in better EPC ratings.
  • Building Orientation: A building’s orientation can influence solar gains and heat retention.

SAP v RD (Reduced Data SAP)


Standard Assessment Procedure (SAP)

The Standard Assessment Procedure is a methodological approach employed for new builds, extensions, and conversions in the UK. It proffers an exhaustive analysis predicated on accurate data derived from building plans and specifications.


SAP assesses the energy costs of space heating, water heating, and lighting. SAP also provides a carbon dioxide emissions rating, which is instrumental in evaluating the environmental impact of the building.

Reduced Data SAP (RdSAP)

Reduced Data SAP, on the other hand, is tailored for existing dwellings. 


It is a more streamlined assessment utilising a reduced dataset, offering a more pragmatic approach to existing buildings. RdSAP incorporates a simplified procedure for deducing energy costs and is instrumental in comparing the energy performance of existing dwellings, thereby determining requisite improvement measures. RdSAPs are going through a significant update in order to help homeowners undertake efficient retrofit solutions.

What Can Air Tightness Do For SAP Rating?


Air tightness is a linchpin in enhancing the SAP rating. It diminishes unwanted draughts and heat loss, resulting in superior energy efficiency. A well-sealed property retains heat more efficiently and requires less energy to maintain a comfortable and healthy living environment. This will now be part of all SAP testing for both new-build and existing dwellings from 2024 and is a key metric for improving your home’s energy efficiency.


Biggest Area of Energy Loss on EPC


Draughts and air leakage through the building envelope – encompassing walls, roof, windows, and doors – is often identified as the most significant area of energy loss in EPC assessments. Making homes less leaky and draughty by improving air tightness can have a very significant impact on the EPC rating.


Wasted Energy in Buildings


Wasted energy is primarily a result of heat loss due to inadequate insulation and air leakage. Rectifying these issues not only boosts the EPC rating but also leads to a substantial reduction in energy bills over time.


What Is Making My EPC Low?


A suboptimal EPC rating can be attributed to a slew of factors:

  • Poor Insulation: Inadequate insulation in key areas leads to considerable heat loss.
  • Air Leakage: Gaps and fissures in the building envelope can cause air leakage, engendering heat loss and higher energy bills.
  • Inefficient Windows and Doors: Windows and doors with broken/blown glazing or poor fitment contribute to energy loss through draughts and inferior U-Values.
  • Lack of Renewable Energy Sources: The absence of renewable energy solutions can also adversely impact the EPC rating.

Your EPC and Part L


Part L Building Regulations in the UK guide us on how to save energy and reduce fuel usage in buildings. Following these rules not only helps reduce our carbon footprint but also plays a big part in boosting a property’s EPC rating. A better EPC rating means the building is more energy-efficient, which is the aim of Part L.


How AeroBarrier UK Can Help Raise Your EPC


AeroBarrier UK offers an innovative solution to augment air tightness, significantly contributing to a better EPC rating. Our unique processes not only assess the air tightness of your property but simultaneously fix any gaps or cracks in the building’s envelope. This can improve your EPC rating, helping you to have works signed off by building control, and save you time and effort by having everything done in a single treatment. 


To find out how we can help your next project, contact a member of our team on 01432 513 499 Or email us at and a specialist will be able to help guide you through the process. 

Discover how you can achieve & exceed airtightness with AeroBarrier.

Discover how you can achieve & exceed airtightness with AeroBarrier.

Have a question?, need a quote or to arrange a FREE demonstration seal at your sites.

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