What is a Domestic Energy Assessment? | EPC Explained
What is a Domestic Energy Assessment? | EPC Explained
What is a Domestic Energy Assessment? | EPC Explained

Understanding how energy is used in your home is important for saving money and reducing environmental impact. This is where a domestic energy assessment comes in. But what is a domestic energy assessment? It's a detailed evaluation of your property’s energy efficiency, carried out by a trained professional (Domestic Energy Assessor) qualified and accredited through an approved accreditation scheme. These assessments help homeowners and landlords identify ways to improve energy performance. The process also generates an Energy Performance Certificate (EPC), a document required for selling or renting a property.
In this post, we will explore how these assessments work, their benefits, and the steps you can take to enhance your home’s energy efficiency.
Key Takeaways
- A Domestic Energy Assessment Identifies Energy Efficiency and Provides an EPC: A domestic energy assessment is a professional evaluation of a property’s energy performance, focusing on factors like insulation, heating systems, and lighting. The assessment generates an Energy Performance Certificate (EPC), a legal requirement when selling or renting a property in the UK.
- EPC Ratings Explain a Property's Energy Efficiency and Provide Improvement Suggestions: EPCs use a scale from A (most efficient) to G (least efficient) to rate a property’s energy efficiency. The certificate highlights key areas for improvement, such as upgrading insulation or heating systems, helping property owners lower energy costs and reduce environmental impact.
- EPCs Benefit Homeowners, Landlords, and Tenants: EPCs are not just regulatory documents; they help property owners comply with legal standards, increase market value, and attract energy-conscious buyers or tenants. With valid EPCs lasting 10 years, they offer actionable insights to improve energy efficiency and reduce carbon footprints.
Domestic Energy Assessment Podcast Chat
For a quick overview of the article in podcast fashion, watch the video below.
What is an Energy Performance Certificate (EPC), and How Does it Relate to the Assessment?
An Energy Performance Certificate (EPC) is an official document that rates the energy efficiency of a property on a scale from A (most efficient) to G (least efficient). It provides detailed information about the property’s energy use, typical energy costs, and recommendations for improving efficiency.
An EPC is directly linked to a domestic energy assessment, as this evaluation gathers the necessary data to produce the certificate. The assessor inspects key aspects of the property, such as insulation, heating systems, and windows, to calculate the energy rating. An EPC is essential for property transactions and rentals, as it is a legal requirement in many cases. It helps buyers, tenants, and landlords understand the energy performance of a building, making it a critical tool for promoting energy efficiency and informed decision-making.

What Happens During a Domestic Energy Assessment?
A domestic energy assessment involves several steps to evaluate a property’s energy performance. Here’s what happens during the survey:
Initial Inspection
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- The domestic energy assessor starts by inspecting the property, taking note of its size, layout, and overall construction.
Insulation Check
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- They examine the insulation in the walls, roof, and floors to assess how well the property retains heat.
Heating Systems Evaluation
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- The assessor reviews the heating system, including the boiler, radiator valves, and controls, to measure efficiency and functionality.
Windows and Doors Assessment
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- They inspect the type and condition of windows and doors, focusing on double glazing, draught-proofing, and thermal performance.
Lighting Analysis
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- Energy-efficient lighting, such as LED light bulbs, is noted as a contributing factor to overall efficiency.
Data Collection
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- Measurements and observations are recorded, including property dimensions, construction materials, and energy usage patterns.
Energy Performance Rating
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- The data is input into approved software that implements the RdSAP methodology to calculate the property’s EPC rating, ranging from A to G.
Recommendations for Improvement
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- The assessor provides advice on upgrades, such as improving insulation or upgrading to a more efficient heating system. The article "Residential energy efficiency interventions: A meta-analysis of effectiveness studies" in Campbell Systematic Reviews examines the impact of various residential energy efficiency measures (REEIs), such as insulation and efficient heat pumps, on reducing energy consumption. It highlights that bundled interventions, implemented after energy audits, significantly cut energy use, particularly for low-income households. However, the study reveals that outcomes vary widely depending on the intervention's implementation and context, emphasising the need for detailed reporting and further research to optimise effectiveness across diverse settings (1).
EPC Issuance
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- After the assessment, the official Energy Performance Certificate is issued, summarising the findings and recommendations.
This process ensures that property owners and tenants receive a correct picture of the building’s energy performance and clear guidance for improvement. Each assessment is also subject to audit by an accreditation body to ensure compliance with required standards. To simplify the process follow our guidance before the assessor arrives to ensure you're properly prepared for your domestic energy assessor visit.
What do the Different EPC Ratings Mean, and How Are They Calculated?
The Energy Performance Certificate (EPC) uses a rating scale from A to G to indicate a property's energy efficiency. An A rating represents excellent energy performance, meaning the property is highly efficient with minimal energy waste. On the other end, a G rating shows very poor efficiency, where the building consumes excessive energy and likely incurs high running costs. The UK government reports that many homes fall into Band D, reflecting moderate efficiency.
Factors That Influence EPC Ratings:
- Insulation: Quality and thickness of wall, roof, and floor insulation.
- Heating Systems: Efficiency of boilers, radiators, and heating controls.
- Windows and Doors: Presence of double or triple glazing and draught-proofing.
- Lighting: Use of energy-efficient bulbs like LEDs.
- Renewable Energy: Systems such as solar panels or heat pumps.
- Age of the Property: Older properties tend to be less energy-efficient.
- Property Type: Flats and maisonettes are more likely to achieve higher ratings than detached homes.
The ratings are calculated using the Standard Assessment Procedure (SAP) or its simplified version, the Reduced Data Standard Assessment Procedure (RdSAP). These methodologies evaluate a property's energy consumption and carbon emissions based on factors like construction materials, heating systems, and energy usage. Assessors collect data during the inspection and input it into specialised software approved by the accreditation body that calculates the EPC rating.
The specific SAP scores for each band are:
A: 92-100
B: 81-91
C: 69-80
D: 55-68
E: 39-54
F: 21-38
G: 1-20
Each EPC also includes a potential efficiency rating, showing how the property could improve with recommended upgrades. The rating is based on both the energy use per square metre of floor area and the energy efficiency measured by fuel costs. By understanding the ratings and how they are determined, property owners can identify areas for improvement and work toward better energy efficiency.
Why do Homeowners And Landlords Need an EPC?
An Energy Performance Certificate (EPC) is more than just a document—it is essential for legal compliance and practical decision-making. Here are the key reasons why homeowners and landlords need an EPC:
Legal Requirement
An EPC is mandatory for selling or renting a property in the United Kingdom. An EPC is required in Scotland for new buildings and certain public buildings. Without an EPC, property transactions cannot legally proceed.
Informed Decision-Making
The EPC provides clear information about a property’s energy efficiency, helping owners and landlords identify areas that need improvement.
Attracting Tenants and Buyers
A good EPC rating makes a property more appealing to tenants and buyers who prioritise energy efficiency to save on utility bills.
Compliance with Government Regulations
Landlords must meet minimum energy efficiency standards (MEES). Properties with an EPC rating below E may require upgrades to comply with regulations. This requirement has been in effect since April 1, 2018, for new tenancies and April 1, 2020, for all existing tenancies.
Improved Market Value
Energy-efficient homes with higher EPC ratings may command higher sale prices or rental values, making them more attractive in the market.
Encouraging Energy Efficiency
By identifying areas for improvement, the EPC encourages homeowners and landlords to adopt energy-saving measures that lower utility costs and reduce carbon footprints.
An EPC is not just a box to check—it is a tool that supports energy efficiency and compliance while offering financial and environmental benefits. Additionally, EPCs are valid for 10 years and can be reused multiple times within that period. However, there are exemptions to the EPC requirement for certain properties, such as listed buildings and temporary structures. In Scotland, failure to provide an EPC when required can result in a minimum fine of £500.
What Should You do After Receiving Your EPC?

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After receiving your EPC, start by reviewing the energy efficiency rating and the recommendations section. Focus on the suggested improvements, which are ranked by cost-effectiveness and potential impact on your rating.
Use your EPC as a guide to plan recommended improvements, considering your budget and energy-saving goals. If you’re a landlord, ensure compliance with energy efficiency regulations. Taking action based on the EPC not only lowers your energy bills but also increases the comfort and potential value of your property.
For a more comprehensive understanding of your building's energy efficiency, consider a Retrofit Assessment to improve insulation, upgrade your boiler, or create long-term improvement plans.
Frequently Asked Questions
The cost of a domestic energy assessment typically ranges from £50 to £120, depending on the property size and location. Larger properties may cost more due to the complexity of the assessment.
Most EPC assessments take between 30 minutes and 1 hour to complete. Larger or more complex properties may require additional time.
No, only qualified and accredited Domestic Energy Assessors (DEAs) are authorized to carry out assessments and issue EPCs. They use specific tools and software to calculate accurate ratings.
EPCs are valid for 10 years. However, if you make significant energy efficiency upgrades, you may want to get a new EPC sooner to reflect the improvements.
Reference List
(1) 2021). Residential energy efficiency interventions: A meta-analysis of effectiveness studies. Campbell Systematic Reviews, 17, e1206. https://doi.org/10.1002/cl2.1206
, , , , , & (Research licensed under CC BY 4.0 DEED.
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