How Is Your EPC Score Calculated?

What is an EPC score?

EPC stands for Energy Performance Certificate. Your EPC score indicates how much energy your home consumes annually for heating and hot water, expressed in kWh per square metre (kWh/m²/year). The lower the number, the more energy-efficient your home.

In addition to the energy score, your home receives an energy label from A+ to F:

The average EPC score in Flanders is around 350 kWh/m²/year — that's a D label. The vast majority of the housing stock has significant room for improvement.

Why does your EPC score matter?

Your EPC score has real consequences:

When selling or renting, a valid EPC certificate is legally required. The label must even be mentioned in every property listing.

When buying a home with an E or F label in Flanders, you're subject to the renovation obligation: you must renovate to at least label D within six years. Fail to comply, and you risk fines of up to €200,000.

For your wallet, a good label makes a noticeable difference. A home with an A label can have a significantly lower energy bill than a comparable property with an E label — and is also worth more on the real estate market.

For subsidies, your EPC label determines whether you qualify for the EPC label premium (up to €5,000 in Flanders) and various renovation grants through programmes like Mijn VerbouwPremie (Flanders), Rénopack (Wallonia), or RENOLUTION (Brussels — though some Brussels subsidies are currently on hold).

What factors determine your EPC score?

An energy assessor considers the building's technical characteristics — not your actual consumption or household appliances. The main factors are:

Insulation — roof, walls, floor, and pipes. Heat loss through the roof alone can account for up to 30%. A well-insulated building envelope is the foundation of a low EPC score.

Windows and doors — single glazing and outdated frames cause significant heat loss. High-performance glazing or triple glazing makes a big difference.

Heating system — an old oil or gas boiler scores considerably worse than a modern condensing boiler or heat pump.

Hot water — how you heat your domestic water (conventional boiler, solar boiler, heat pump boiler) is factored in.

Ventilation — a controlled ventilation system scores better than natural ventilation.

Renewable energy — solar panels, a solar boiler, or heat pump lower your EPC score because the home covers part of its own energy needs.

Property type — an apartment has fewer exterior walls than a detached house and therefore loses less heat, resulting in a lower EPC score.

How does the calculation work?

You cannot calculate your official EPC score yourself. Only a certified energy assessor (type A in Flanders, or an accredited PEB certifier in Wallonia and Brussels) is authorised to do so.

The process has three steps:

1. On-site inspection. The energy assessor visits your property and inventories all relevant characteristics: insulation materials, windows, heating system, ventilation, solar panels, construction year, surface area, and building type.

2. Data entry into certified software. All data is entered into the standardised software platform regulated by VEKA (the Flemish Energy and Climate Agency). The calculation is fully regulated — every assessor uses the same methodology.

3. Issuance of the EPC certificate. After the calculation, you receive the official certificate with your energy score, energy label, and specific recommendations for improvement.

Important: gather your documentation. When the assessor cannot verify the thickness or type of insulation (for example, when it's hidden behind finishing), they are required to use default values. These default values are always unfavourable and push your score up. So before the visit, gather all invoices, certificates, and technical data sheets for your insulation, windows, boiler, solar panels, and any other energy-saving investments.

Can you estimate your EPC score in advance?

The official calculation is the assessor's job. But you can get a first estimate to know roughly where you stand — and which renovations would have the most impact.

What does an EPC assessment cost?

The price of an EPC assessment depends on the type and size of your property. On average, expect to pay between €150 and €350 excluding VAT. A studio or apartment is typically cheaper than a large detached house.

An EPC certificate is valid for 10 years. Note: when selling in Flanders, you need a certificate issued in 2019 or later.

From score to action

Knowing your EPC score is step one. The next step is understanding which renovations make the biggest difference — and in what order to tackle them. The right approach prevents double work and maximises your subsidies.

At EPCBuddy, we guide you through the entire journey: from an initial EPC to map out your situation, through the right renovations in the right sequence, to a new EPC that proves your improvement in black and white.