One of the most effective ways to make your home more energy‑efficient? External wall insulation. By insulating your exterior walls, you reduce heat loss, lower your energy bills, and significantly improve your EPC score.
Depending on your type of dwelling, your EPC value can drop by 20 to 80 kWh/m² per year — often enough to move from energy label F to D or even C.
Why your EPC score is so important
The EPC (Energy Performance Certificate) indicates how energy‑efficient your home is. The lower the score, the less energy is needed for heating. Since the Flemish renovation obligation, improving your EPC score has become particularly important (and in some cases mandatory):
- Bought a home with EPC label E or F? You must reach at least label D within 5 years.
- A better EPC score increases the value of your property and makes it more attractive on the market.
EPC improvement through external wall insulation
On average, 25% to 30% of heat loss occurs through external walls. It therefore makes sense that insulating these walls has a major impact on both your energy consumption and your EPC score.
In figures:
- An average home can save 2,000 to 12,000 kWh per year with wall insulation.
- This translates into an EPC improvement of 20 to 80 kWh/m² per year, depending on the building type and existing insulation level.
- In some cases, insulation alone can move a home from label F to D or even C.
How much difference does it make?
The exact improvement depends on the type of home, the current insulation condition, and the materials used. As a guideline, you can expect the following improvements:
| Type of dwelling | Expected EPC reduction |
|---|---|
| Apartment | 10 – 30 kWh/m²·year |
| Terraced house | 20 – 50 kWh/m²·year |
| Semi‑detached house | 30 – 60 kWh/m²·year |
| Detached house | 40 – 80+ kWh/m²·year |
For an exact calculation, an EPC simulation by a certified energy expert is required. These averages nevertheless give a good indication of what is achievable.
Practical example
Suppose you live in a detached house with a usable floor area of 150 m². The external walls are poorly insulated or not insulated at all. You choose external wall insulation with 10 cm insulation and a λ‑value of 0.035 W/mK.
In that case, your EPC score can drop from 500 to 420 kWh/m²·year.
That is an improvement of 80 kWh/m²·year × 150 m² = 12,000 kWh of energy savings per year.
This reduction is often sufficient to move from energy label F to D — a significant improvement that may also qualify for subsidies or a more favourable renovation loan.
Which type of external wall insulation suits your home?
At Idelco Insulation, we distinguish two main applications for external wall insulation:
1. Cavity wall insulation (between inner and outer wall leaves)
This is often the fastest and most cost‑effective method, especially for existing homes with an open cavity. The insulation is placed inside the cavity wall, providing an invisible yet highly efficient thermal upgrade.
Suitable products:
- α‑therm Universal
- α‑therm WALL
- α‑therm WALL FR
- Blue PIR WALL
- Blue PIR WALL FR
2. External façade insulation (for renovation or retrofitting)
Insulation panels are installed on the outside of the façade and finished with a ventilated cladding system such as panels, timber, or brick slips. External façade insulation is ideal if you want to improve both the appearance and the energy performance of your building envelope.
Suitable products:
- α‑therm WALL+
- Blue PIR WALL+
What thickness do you need?
The better you insulate, the greater the impact on your EPC score. An insulation thickness of 10 to 14 cm of PIR is often sufficient to meet current energy standards.
Idelco Insulation offers PIR insulation with a λ‑value of 0.022 W/mK — meaning maximum insulation with minimal thickness.
Additional benefits of external wall insulation
Besides a lower EPC score, you also benefit from:
- Lower energy bills
- Increased living comfort: no more cold walls, stable indoor temperatures
- Reduced noise pollution
- Aesthetic upgrade of your façade
- Added property value
Am I eligible for a subsidy?
Yes. In Flanders, you may be eligible for façade insulation subsidies via Fluvius, subject to certain conditions. Your EPC label itself may also entitle you to additional financial support during renovation.
Always check the most up‑to‑date information at www.premiezoeker.be or consult a certified energy expert.
Which solution suits your home?
Every building is different. That’s why choosing the right insulation solution is essential. With the Blue PIR range from Idelco Insulation, you benefit from:
- Belgian production with short lead times
- Excellent thermal performance
- Multiple solutions for both cavity walls and façades
Frequently asked questions
Can I combine external wall insulation with other energy‑saving measures?
Absolutely. External wall insulation works well in combination with roof insulation, high‑performance glazing, or a heat pump. Together, these measures can significantly reduce your EPC score and may qualify you for additional subsidies.
How quickly does external wall insulation pay for itself?
The payback period depends on the insulation value, energy prices, and your heating system.
Does it make sense to insulate only one façade?
That depends on the orientation and insulation status of the rest of the building. In many cases, it makes sense to start with the coldest or most exposed façades, but a complete insulation envelope delivers the greatest EPC improvement.
Can I install external wall insulation myself?
Cavity wall insulation is best carried out by a professional. For façade insulation with a ventilated system, technical detailing and correct installation are crucial. Incorrect installation can lead to moisture problems or loss of insulation performance.
Conclusion
External wall insulation has a direct and measurable impact on your EPC score. The thicker and higher‑quality the insulation, the greater the gains in comfort, property value, and energy efficiency. The right PIR insulation panels make the difference — and you’ll find them at Idelco Insulation.
Need advice or curious about the price?
Get guidance from an expert and discover which solution best suits your home.
