Want to know how energy-efficient your home is? Use our free EPC calculator to estimate your property's energy score and EPC or PEB rating. Answer questions about your insulation, windows and heating to receive an indicative result.
This calculation is indicative and does not replace an official EPC certificate.
Answer a few questions about your home and its systems to receive an indicative estimate of its energy performance.
These details help us account for the region and your home's characteristics when producing an indicative estimate.
Enter the original construction year of the property.
Enter your best estimate of the heated floor area.
This calculator provides an indicative estimate and does not replace an official EPC or PEB certificate.
The energy score indicates how efficiently a home performs under standardised conditions. It is expressed in kilowatt-hours of primary energy per square metre per year, or kWh/(m² year).
The lower the energy score, the more energy efficient the property. The calculation considers factors such as roof, wall and floor insulation, windows, heating, domestic hot water, ventilation and renewable energy.
ENERGY SCORE
The score represents the calculated annual energy performance per square metre of the property. A home with a lower score generally requires less primary energy under the same standardised conditions.
ENERGY LABEL
The numerical energy score is converted into an energy label. Flanders, Brussels and Wallonia each use their own label scale and threshold values.
THEORETICAL CALCULATION
Energy performance certificates use standardised assumptions so that homes can be compared fairly. Your actual energy consumption may be higher or lower depending on occupancy, heating behaviour and personal habits.
Energy label thresholds differ between Belgium's regions. See how EPC and PEB scores are classified in Flanders, Brussels and Wallonia.
In Flanders, residential EPC labels range from A+ to F. A lower energy score indicates a more energy-efficient home.
The displayed thresholds follow the Flemish residential EPC label scale. Only an official EPC can determine the final label of a property.
Improving energy performance usually starts by reducing heat loss. Roof and external wall insulation can therefore play an important role in improving a home's calculated energy performance.
If your home has a suitable uninsulated cavity wall, cavity wall insulation can reduce heat loss through the external walls. Existing wall insulation is taken into account when assessing energy performance.
View cavity wall insulationAn inadequately insulated roof can lead to significant heat loss. Depending on the property, either the roof itself or the attic floor can be insulated to improve the thermal envelope.
View roof insulationWhen cavity wall insulation is not possible or sufficient, external wall insulation can provide an alternative. The insulation layer is combined with a new rendered façade finish.
View external insulation with renderIn addition to insulation, energy performance calculations also consider windows and doors, heating, domestic hot water, ventilation and renewable energy.
High-performance or triple glazing can reduce heat loss through windows, particularly where single glazing or older double glazing is still present.
The efficiency and type of heating system influence the calculated energy use of the property.
Solar panels and solar thermal systems can contribute to energy performance by supplying part of the home's energy from renewable sources.
The measure with the greatest impact varies from one property to another. An official EPC or PEB assessment and its recommendations provide more detailed information for the specific property.
Our calculator provides an initial estimate of a home's energy performance based on the information you enter. An official EPC or PEB assessment uses more detailed technical data and follows the certification methodology of the relevant region.
The calculation considers factors such as property type, construction year, floor area, insulation, glazing, heating, ventilation and renewable energy.
When certain technical details are unknown, the calculator has to use assumptions. The actual official energy score may therefore differ from the estimate.
Only an EPC or PEB certificate produced according to the relevant regional certification methodology can determine the official energy score and label.
Important: use this result as an initial indication of your home's energy performance, not as an official EPC or PEB certificate.
Find answers about energy scores, energy labels, our calculator and improving your home's energy performance.
A lower energy score indicates better energy performance. In Flanders, an EPC score between 1 and 100 kWh/(m² year) corresponds to label A, while a score of 0 or below corresponds to A+. Brussels and Wallonia use their own PEB scales and thresholds, so scores should always be interpreted according to the region where the property is located.
There is no single minimum Rd value that applies to every roof renovation in Belgium. In Flanders, new roof or attic-floor insulation must achieve an Rd value of at least 4.5 m²K/W to qualify for Mijn VerbouwPremie in 2026, subject to the other eligibility conditions.
In Wallonia, the temporary Primes Habitation 2025–2026 scheme ended on 30 September 2026. New projects are subject to different financing conditions through Rénopack and Rénoprêt.
The insulation thickness needed to achieve a particular Rd value depends on the material's thermal conductivity, known as its lambda value.
An energy performance score is calculated using the energy-related characteristics of the property. These include the size of the home, roof, wall and floor insulation, windows and doors, heating, domestic hot water, cooling, ventilation and solar energy systems. Standardised assumptions are used so that the energy performance of different homes can be compared.
kWh/(m² year) expresses the calculated annual primary energy performance per square metre of floor area. A lower figure generally indicates a more energy-efficient property. It is a theoretical energy performance figure and is not the same as the actual consumption shown on your energy bills.
No. The Nu-Isoleren calculator provides an indicative estimate based on the property information you enter. The result is not an official EPC or PEB certificate and cannot replace an official certificate required for purposes such as selling or renting a property. Official certificates must be prepared according to the applicable regional certification rules by an authorised professional.
An official EPC or PEB assessment uses a detailed regional calculation methodology and more technical information about the building. An online calculator does not always have access to all of these details and therefore has to make assumptions for some inputs. The estimated result can consequently be higher or lower than the score on an official certificate.
Yes. Roof, wall and floor insulation are taken into account when assessing the energy performance of a home. Improving insulation can reduce heat loss and contribute to a better energy score. The exact effect depends on the existing building, insulation levels, technical systems and other characteristics of the property.
EPC is the term commonly used in Flanders for the energy performance certificate. Brussels and Wallonia mainly use PEB, short for Performance Énergétique des Bâtiments. They serve a similar purpose, but each Belgian region uses its own calculation methodology, energy label scale and thresholds.
No. EPC and PEB scores are theoretical calculations based on standardised conditions so that properties can be compared consistently. Actual consumption also depends on factors such as occupancy, indoor temperature, heating habits and how much of the property is heated. As a result, actual energy consumption can differ substantially from the calculated score.
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