EPC Ratings

What is an EPC rating?

An Energy Performance Certificate (EPC) rating for domestic homes in the UK is a measure of a property's energy efficiency. The rating scale runs from A (most efficient) to G (least efficient). The EPC provides information on how much energy a home uses, the carbon emissions produced, and recommendations for improvements that could enhance energy efficiency.

EPCs are required when a property is built, sold, or rented. They help potential buyers or tenants understand the energy costs and environmental impact of a home. The certificate is valid for ten years, and energy efficiency improvements can improve the rating.

Who scores a property’s EPC rating?

A Domestic Energy Assessor (DEA) will conduct an examination of the property to establish the energy performance. This could include an initial assessment of the performance of the building’s fabric, such as windows and walls, as well as its heating system.

Data will be collected about the property's characteristics, such as its size, construction materials, insulation levels, heating systems and fuel source. The DEA will then provide recommendations on improvements that could enhance energy efficiency, which in turn should reduce energy bills and improve the EPC rating. Finally, an EPC will be issued, and uploaded to the Government’s website1.

DEAs must be accredited and follow specific guidelines to ensure their assessments are accurate and reliable.

How is this scored?

DEAs must follow a methodology such as RdSAP (Reduced Data Standard Assessment Procedure) or SAP (Standard Assessment Procedure). These are procedures for calculating the energy efficiency of a dwelling and creating an EPC.

RdSAP

• Used for: Existing homes where detailed data may not be available
• Details: It uses a simplified approach, relying on standard assumptions and less detailed information on building elements. Mitigating drawbacks associated with the assumption-based approach is discussed in PAS 2035
• Outcome: Calculates a figure between 1 and 100+ which corresponds with an EPC band rating2, and allows the generation of the EPC certificate

SAP

• Used for: Predominantly for new build homes but can be used for existing homes is enough data is available
• Details: Requires more detailed information about the property’s construction, heating systems, insulation, and energy use than RdSAP. Uses manufacturer specifications to calculate the performance of each building element
• Outcome: As well as a SAP score, it provides a comprehensive analysis of energy efficiency and carbon emissions, with more granularity and accuracy than RdSAP

Both methods aim to help homeowners and potential buyers understand the energy efficiency of a property, identify areas for improvement, and comply with legal requirements for EPCs when selling or renting homes.

For more information, see the following resources:

• Energy performance certificates explained, Energy Saving Trust
• What is the difference between SAP and RdSAP?

If you require a more detailed understanding of your property, conducting a complete retrofit assessment will be more thorough than the standard assessments for EPC rating certificates. This will also help to upgrade the EPC rating if you have had recent measures improved at the property.

What characteristics inform the EPC rating?

Several key elements influence an EPC rating for a domestic property in the UK:

• Insulation levels: The type and quality of insulation in walls, roofs, and floors significantly impact energy efficiency
• Heating systems: The type of heating system (e.g., gas, electric, low carbon sources) and its efficiency play a crucial role
• Windows and doors: The quality and type of glazing (single, double, or triple) and the overall condition of windows and doors affect heat retention
• Lighting: The proportion of low-energy using light bulbs such as LEDs appliances, is assessed
• Construction: The materials and original construction type of the property can affect thermal performance (for example, whether it has solid brick or cavity brick walls)
• Ventilation: The type and quality of ventilation systems can influence the EPC rating
• Renewable energy sources: The presence of solar panels, heat pumps, or other renewable technologies can affect the rating

These factors are analysed during the assessment to determine the property’s energy efficiency and environmental impact, leading to the final EPC rating.

What obligation is there to gain above an EPC rating or C or above?

In the UK, there are specific obligations regarding the Energy Performance Certificate (EPC) ratings for domestic homes, particularly in the context of rental properties:

• Minimum Energy Efficiency Standards (MEES): Since April 2018, landlords must ensure that their properties have a minimum EPC rating of E or above when renting them out
• From 2030: This obligation will extend to new tenancies and renewals, requiring a minimum EPC rating of C or above for most residential rental properties

Some properties may be exempt from these regulations, such as listed buildings or properties where improvements would be not cost-effective. An official government exemption notice must be granted if properties are performing under the required EPC rating for them to be rented out.

What are the recommendations following an EPC?

An EPC will score your current and potential energy performance. The ‘potential’ rating indicates the rating that could be achieved if the recommended improvements are implemented. The recommendations may include:

• Upgrading insulation (walls, roofs, floors)
• Installing low carbon heating systems (like heat pumps)
• Improving window glazing (e.g., double or triple glazing)
• Installing renewable energy sources (like solar panels)

The potential rating and recommendations will also indicate the estimated costs for the improvements and potential savings on energy bills, helping landlords understand the financial implications of suggested upgrades to improve an EPC rating.

Why does it include current and potential EPC ratings with recommendations?

Landlords and tenants can benefit from understanding both current and potential EPC ratings.

• Current ratings help to inform decision making on energy efficiency measures, ensure compliance to regulation and aid energy budgeting and costs
• Potential ratings allow you to see a property’s energy performance potential when recommended measures are installed. This can help landlords plan investments effectively and assess the potential energy savings

For more information, see the following resource:

• EPC benefits, EPC Home

What are the drawbacks from EPC ratings?

In some cases, EPC can present challenges to retrofit and inconsistency of data’s accuracy. For example, an assumption that a property’s standard occupancy is 2 adults and 2 children may be incorrect and effect the general use of heating in the property. However, the disadvantages around accuracy is outweighed by EPCs now being very familiar and easy to understand to a range of stakeholders.