What Does an EPC Assessment Include? A Complete Guide for London Property Owners

If you are selling, letting or preparing a property for the market, you may need an Energy Performance Certificate (EPC). But what actually happens during an EPC assessment, and what does the assessor look at?

An EPC assessment examines the energy efficiency of a property and produces an energy rating from A to G, with A representing the highest level of energy efficiency. In England and Wales, an EPC is generally valid for 10 years unless a newer certificate is produced for the property. GOV.UK guidance

For London homeowners, landlords and property professionals, understanding the assessment process can make booking an EPC much easier.

What Is an EPC Assessment?

An EPC assessment is an inspection carried out by an accredited energy assessor to collect information about a property’s construction, heating, insulation and energy-related features.

The information collected during the assessment is used to calculate the property’s energy efficiency rating and produce the EPC.

An EPC also provides recommendations that can help improve the property’s energy efficiency.

If you are preparing a property for sale or rental, you can arrange a professional Domestic EPC assessment in London with EPC Rate London.

What Does an EPC Assessor Check?

During an EPC assessment, the assessor will typically look at several important features of the property.

1. Property Size and Layout

The assessor needs information about the property itself, including its size, layout and the number of rooms.

Measurements and property characteristics help determine how the building performs from an energy-efficiency perspective.

This is one reason why the assessor needs access to the property rather than simply issuing an EPC based on photographs.

2. Walls, Roof and Floor

The construction of the property can have a significant effect on energy efficiency.

The assessor may consider factors such as:

Wall construction
Roof construction
Floor construction
Insulation
Extensions or alterations
Age and type of the property

Where appropriate evidence is available, information about insulation and construction can be taken into account during the assessment.

3. Windows and Glazing

Windows are another important part of an EPC assessment.

The assessor may look at:

Single or double glazing
Window type
Glazing characteristics
Frame type
Approximate age or condition where relevant

Better-performing windows can help reduce heat loss and may contribute to improved energy efficiency.

4. Heating System

The main heating system is an important part of the assessment.

The assessor may record information about the property’s:

Boiler or heating system
Heating controls
Fuel type
Hot water system
Heating distribution

If you have documentation relating to your heating system, keeping it available can help provide the assessor with accurate information.

5. Hot Water

The assessor also considers how hot water is produced and stored.

This can include looking at the hot water cylinder, heating system and insulation where relevant.

Accurate information helps ensure that the EPC reflects the property as closely as possible.

6. Lighting

Lighting can also contribute to the property’s energy assessment.

The assessor may record the proportion and type of energy-efficient lighting installed throughout the property.

Replacing inefficient lighting can be a relatively simple way to improve the energy performance of a home.

7. Renewable Energy Features

If the property has renewable or low-carbon technologies, these may also be relevant to the assessment.

Examples can include:

Solar photovoltaic panels
Solar water heating
Heat pumps
Other renewable technologies

If you have installation documentation or other relevant paperwork, it can be useful to have it available for the assessment.

What Happens During an EPC Inspection?

An EPC assessment is generally straightforward.

The assessor visits the property and collects the information required to calculate its energy performance.

You should make sure the assessor can access the relevant areas of the property and that important information about heating, insulation or improvements is available where possible.

The assessor then uses the collected information and approved methodology to produce the EPC.

For properties in London, choosing an experienced and appropriately accredited assessor is important. GOV.UK states that EPCs must be produced by an accredited energy assessor who belongs to a government-approved accreditation scheme. Read the official EPC guidance

How Long Does an EPC Assessment Take?

The time required depends on the size, type and complexity of the property.

A straightforward home can usually be assessed relatively quickly, while larger or more complicated properties may require additional time.

The important point is that the assessor needs sufficient access and information to complete an accurate assessment rather than simply rushing through the property.

If you need an EPC quickly, EPC Rate London offers fast EPC services across London with turnaround options advertised on its website.

What Information Is Included in an EPC?

Once the assessment is complete, the EPC provides information about the property’s energy performance.

This includes:

Energy efficiency rating
Environmental impact information
Typical energy-related information
Recommendations for improving energy efficiency
Details about the property and its energy performance

The rating uses a scale from A to G, with A being the most efficient and G the least efficient. GOV.UK confirms that an EPC also includes steps that can improve energy efficiency and potentially reduce energy costs. Check the official GOV.UK EPC information

How Long Is an EPC Valid?

A valid EPC is generally valid for 10 years.

You do not normally need a completely new EPC every time a property changes hands or tenants, provided there is still a valid certificate and a newer certificate has not replaced it.

Before arranging another assessment, it can therefore be worth checking whether the property already has a valid EPC.

You can use the official GOV.UK energy certificate search to check an existing certificate by property details or certificate number.

What If My EPC Rating Is Low?

A lower EPC rating does not necessarily mean that the property cannot be sold or rented.

Instead, the EPC provides information about the property’s current energy performance and recommendations for potential improvements.

Depending on the property, possible improvements could include:

Improving insulation
Upgrading heating controls
Improving glazing
Installing more efficient lighting
Improving hot water insulation
Considering renewable energy technologies

The most appropriate improvements depend on the individual property, so recommendations should be considered alongside the property’s condition, cost and suitability.

For landlords, understanding the current EPC rating can also be useful when planning property improvements.

If you are a landlord, you can also read our guide on EPC Certificates: What Landlords Need to Know in 2026 for additional information.

Do I Need an EPC to Sell or Rent My Property?

In England, an EPC is generally required when a property is being sold or rented out, and it must be commissioned before the property is marketed.

GOV.UK advises that sellers and landlords need to have an EPC when selling or renting a property, subject to specific exemptions. See the official GOV.UK requirements

This makes arranging the EPC an important part of preparing a property for the market.

How Much Does an EPC Cost in London?

The cost of an EPC depends on factors such as the property type, size and location.

EPC Rate London currently lists domestic EPC pricing starting from £45 for a studio flat, with other prices depending on the number of bedrooms. View current EPC pricing

Because prices and services can change, it is best to check the current pricing before booking.

How to Prepare for an EPC Assessment

A few simple steps can make the assessment easier.

Before the assessor arrives:

Make sure the property is accessible.

The assessor needs to inspect the relevant parts of the property.

Have heating information available.

If you have documentation for your boiler, heating system or recent improvements, keep it available.

Provide information about insulation or improvements.

Evidence of improvements can be useful where relevant.

Make sure rooms and relevant areas can be accessed.

Avoid blocking access to important equipment or areas that the assessor may need to inspect.

Tell the assessor about relevant improvements.

If you have installed new windows, insulation, solar panels or a new heating system, mention this during the assessment.

Why Choose a Professional EPC Assessor?

An EPC is not simply a document for your property listing. It provides information about the property’s energy performance and can influence how buyers, tenants, landlords and property professionals understand the building.

Using an accredited assessor helps ensure that the assessment is carried out in accordance with the relevant requirements.

EPC Rate London provides EPC services across London, including domestic and commercial assessments, with additional property services such as professional floor plans and property photography for property marketing.

You can learn more about the company and its experience on the EPC Rate London About page.

Check Your EPC Before You Market Your Property

If you are planning to sell or rent a London property, don’t leave the EPC until the last minute.

First, check whether the property already has a valid certificate using the official GOV.UK energy certificate search.

If you need a new assessment, arrange it before marketing the property so that your EPC is ready when required.

A professional EPC assessment can give you a clearer understanding of your property’s energy performance and the improvements that may help it become more efficient.

Need an EPC in London?

If you need an EPC for a property in London, EPC Rate London provides professional EPC assessments with pricing options for different property types.

Ready to arrange your assessment? Book your EPC online and submit your property details and preferred date.

You can also check the latest EPC pricing or contact EPC Rate London if you have questions about your property requirements.

Whether you are a homeowner preparing to sell, a landlord preparing to let a property or an estate agent managing multiple properties, having the right EPC in place can help keep your property plans moving forward.

Frequently Asked Questions

How long is an EPC valid?

An EPC is generally valid for 10 years unless it is replaced by a newer EPC. GOV.UK

What does an EPC assessment check?

An EPC assessment considers aspects of a property’s construction and energy performance, including walls, roof, floor, insulation, windows, heating, hot water and lighting.

Do I need an EPC to rent out my property?

Generally, yes. An EPC is required when a property is rented out, subject to specific exemptions and requirements. GOV.UK guidance

Can I check my existing EPC online?

Yes. You can use the official GOV.UK energy certificate service to search for an existing EPC.

What rating does an EPC use?

EPCs use an A–G energy efficiency scale, with A representing the highest level of energy efficiency and G the lowest.

Can I improve my EPC rating?

Yes. An EPC includes recommendations for potential energy-efficiency improvements. The most suitable improvements depend on the property and its existing features.

How much does an EPC cost in London?

Prices vary depending on the property. EPC Rate London currently advertises domestic EPCs from £45. Check the latest pricing before booking.

Final Thoughts

An EPC assessment is an important part of preparing a property for sale or rental in London. Understanding what the assessor checks, what information is included in the certificate and how long the EPC remains valid can make the process much simpler.

Before marketing your property, check whether you already have a valid EPC. If you need a new certificate, choose an appropriately accredited assessor and make sure the relevant property information is available.

For professional EPC services across London, book your EPC assessment online and arrange your assessment with EPC Rate London.