Improve your EPC score with better insulation

What is an EPC score and how can you improve it?

The Energy Performance Certificate, commonly known in Flanders as the EPC, indicates how energy-efficient a house or apartment is. The certificate assigns an energy label ranging from A+, for highly energy-efficient properties, to F, for highly energy-intensive properties.

In addition to the label, the EPC also includes an energy score. This is expressed in kilowatt-hours per square metre of usable floor area per year, or kWh/m² per year. The lower the score, the more energy-efficient the property is considered to be.

An EPC is required in Flanders for situations including the sale, another notarial transfer or the rental of a residential property. It gives prospective buyers and tenants insight into the building’s energy performance and includes recommendations for improving it.

Why is a good EPC score important?

A good EPC score generally indicates that a property is better insulated and uses energy more efficiently. This may contribute to:

• reduced heat loss;
• lower energy consumption;
• improved indoor comfort;
• a more attractive property when selling or renting;
• better preparation for future energy standards.

In Flanders, a renovation obligation also applies to houses and apartments with an E or F label that have been purchased since 1 January 2023. The new owner must renovate the property within the applicable period so that it achieves at least a D label.

Improving the EPC score may therefore not only help reduce energy use, but also help the property comply with legal requirements and become more future-proof.

Where is energy lost in a home?

Heat can be lost through several parts of a property, including:

• an inadequately insulated roof;
• uninsulated or poorly insulated external walls;
• outdated windows and doors;
• an uninsulated floor;
• thermal bridges;
• air leaks and gaps;
• an outdated heating system;
• insufficiently controlled ventilation.

The exact contribution of each element varies considerably from one property to another. The year of construction, the shape and size of the building, the existing insulation, the technical systems and the occupants’ behaviour all play a role.

It is therefore better not to rely solely on general percentages, but to have the property assessed individually. The EPC itself also includes recommendations that can help identify which renovations may be relevant to your home.

Roof insulation: reduce heat loss through the roof

The roof forms a major part of a building’s external envelope. If it is insufficiently insulated, a significant amount of heat may be lost. Roof insulation is therefore often a logical first step in an energy renovation.

The most suitable insulation method depends on the type of roof and on how the rooms beneath it are used.

Insulating a pitched roof

A pitched roof can be insulated in several ways:

• between the rafters or roof timbers;
• beneath the existing roof structure;
• externally using a sarking roof system;
• by insulating the attic floor when the attic is not heated.

During a complete roof renovation, the insulation can be installed together with a new roofing underlay and roof covering. This allows the different layers to be properly coordinated from a technical perspective.

Insulating a flat roof

A warm roof system is generally recommended for a flat roof. In this type of construction, the insulation is installed above the structural deck and beneath the waterproof roof covering.

For flat roofs, Faccader works with systems including PIR insulation and finishes in bituminous roofing or EPDM. The most suitable build-up depends on the existing structure, the available height, drainage and the technical condition of the roof.

Facade insulation: protect the entire property

Uninsulated external walls can also be responsible for significant heat loss. With external wall insulation, insulation boards are fitted to the outside of the existing walls. The insulation system is then finished with a material such as render or brick slips.

One major advantage is that the insulation layer continues around a large part of the building. This can reduce certain thermal bridges while preserving the available living space inside the property.

External wall insulation can also combine several improvements:

• better thermal performance;
• increased indoor comfort;
• protection of the existing external walls;
• a completely renewed appearance;
• a reduced risk of cold internal wall surfaces and surface condensation, provided the complete system is installed correctly.

The correct insulation thickness and finish must always be adapted to the existing facade, the connections around windows and doors, the roof edges and any applicable planning regulations.

Windows and doors

Outdated glazing and poorly fitting windows or doors can also cause heat loss and draughts. High-performance glazing performs significantly better than single glazing, but the glass is only one part of the complete window system.

The following elements are also important:

• the insulation value of the window frames;
• the airtightness of the connections;
• the position of the windows in relation to the facade insulation;
• the connection between windows, sills and external walls;
• adequate ventilation throughout the home.

When windows and external wall insulation are installed at different times, the connections should be carefully planned in advance. This helps prevent unnecessary thermal bridges or later adjustment work.

Floor insulation

An uninsulated floor above the ground, a basement or a crawl space may feel cold and allow heat to escape. Floor insulation can therefore improve both energy performance and indoor comfort.

Depending on the construction, insulation may be installed:

• above the existing floor;
• beneath the floor slab;
• against the ceiling of a basement or crawl space.

The available build-up height, moisture conditions and existing floor construction determine which method is technically possible.

Heating, hot water and renewable energy

The EPC does not only take the building envelope into account. Heating and domestic hot-water systems, ventilation and the presence of renewable-energy technologies also affect the energy score.

After improving the insulation, it may be worthwhile reviewing the technical systems as well. A well-insulated home requires less heating capacity.

Possible measures include:

• a more efficient heating system;
• a heat pump where the building is suitable;
• correct heating controls;
• insulation of heating pipes;
• solar panels;
• a suitable ventilation system.

The best approach is generally to reduce the property’s heat loss first and then adapt the technical systems to the building’s new requirements.

How much can your EPC score improve?

It is not possible to assign a reliable fixed number of EPC points in advance to roof insulation, facade insulation or new windows. The final improvement depends on factors including:

• the current EPC score;
• the existing insulation;
• the surface area of the roof, facades, windows and floors;
• the insulation materials used and their thickness;
• the compactness of the building;
• the heating and hot-water systems;
• ventilation and airtightness;
• renewable-energy systems;
• the supporting documents available to the EPC assessor.

Statements such as “facade insulation always improves your EPC by 100 points” are therefore not reliable for every property. An energy assessor can calculate the potential impact much more accurately based on the specific characteristics of your building.

A step-by-step plan for improving your EPC score

Step 1: review your current EPC

Start with the existing EPC and look beyond the label. Read the recommendations and check which parts of the property are considered poorly insulated or outdated.

If you do not yet have a valid EPC, you can appoint an accredited energy assessor to prepare one.

Step 2: gather technical information

Collect invoices, technical data sheets, plans and photographs of previous renovation work. Without valid supporting evidence, the EPC assessor may not be able to fully include certain existing insulation measures in the calculation.

After new work, always keep:

• invoices;
• product data sheets;
• insulation thicknesses;
• lambda values;
• photographs taken before and during installation;
• information about windows and glazing;
• details of heating systems;
• inspection and completion documents.

Step 3: improve the building envelope

In many older homes, the main priorities are the roof, external walls, windows and floor. The order in which these measures should be carried out depends on the technical condition of the property and the available renovation budget.

If the roof is worn or leaking, combining roof renovation with insulation may be the most logical solution. If the facades are damaged or poorly insulated, external wall insulation with a new facade finish may be more suitable.

Step 4: coordinate the different renovation measures

Plan the connections between:

• roof insulation and facade insulation;
• facade insulation and windows;
• roof edges and rainwater drainage;
• plinths and ground level;
• insulation and ventilation;
• insulation and heating systems.

A well-designed renovation plan prevents newly completed work from having to be altered later.

Step 5: obtain a new EPC

The EPC score is not updated automatically after the work has been completed. Have a new EPC prepared so that the improved energy performance is officially recorded.

Provide the energy assessor with all available supporting documents.

Grants and financial benefits

Flemish grants may be available for certain renovation and insulation measures. The conditions and grant amounts depend on factors including income, the type of building, the work carried out and the date of application. The rules for Mijn VerbouwPremie changed from 1 March 2026, meaning that not every applicant category receives support for the same measures. Always check the current conditions before planning your renovation.

For renovation work on a property that is at least ten years old, a reduced VAT rate of 6% may apply under certain conditions. Among other requirements, the work must be invoiced directly to the final user and the property must be used mainly as a private residence.

Avoid broad claims such as “every renovation qualifies for a grant” or “insulation work always provides a tax reduction”. The rules and conditions vary according to the situation and may change.

Faccader supports your roof and facade renovation

With more than 15 years of industry experience, Faccader helps improve the external envelope of your home. We carry out roofing and facade work throughout Flanders and identify solutions suited to your building, requirements and budget.

Our services include:

• renovation and insulation of pitched roofs;
• renovation and insulation of flat roofs;
• bituminous roofing and EPDM;
• PIR insulation;
• external wall insulation;
• facade finishing with render;
• brick slips;
• spray cork;
• roof and facade repairs.

We guide the work from the initial inspection through to the final finish. For an exact calculation of your future EPC score, you should consult an accredited energy assessor.

Would you like to make your home more energy-efficient?

Improving your EPC score begins with a carefully planned renovation strategy. By first having the technical condition of the roof and facade assessed, you can make targeted decisions and avoid unnecessary costs.

Contact Faccader for free advice and a no-obligation quotation for your roof or facade renovation.