Roof insulation has a direct impact on your energy bill and living comfort. You lose less heat in the winter and keep the heat out in the summer. Whether you live in an old or new house, insulating your roof is always a smart move. This article explains everything you need to know about subsidies, costs, and various methods.
Subsidy for roof insulation 2025
In 2025, you can apply for the ISDE subsidy for roof insulation. You'll receive a minimum of €16.25 per square meter of insulated roof surface. If you combine the insulation with a second energy-saving measure, such as underfloor insulation or solar panels, the subsidy doubles.
An additional bonus of €1.25 per square meter is also available for environmentally friendly insulation. This includes protecting bird or bat nesting sites during insulation.
The application is processed via the Netherlands Enterprise Agency (RVO). Please note conditions such as a minimum surface area of 20 m².
Roof insulation inside
Insulating the inside of the roof is a practical option if the roof covering is still in good condition and you don't want to do any major renovations. With this method, the insulation material is placed on the inside of the roof sheathing.
It's important to install a vapor barrier. Without it, moisture can accumulate behind the insulation, leading to mold or wood rot.
This method is relatively cheap and quick to implement, but you will lose some space inside your attic or loft.
Exterior roof insulation
With exterior insulation, also called a "sarking roof," the material is placed on top of the roof sheathing. This is especially suitable for renovations where the roof covering will be replaced anyway.
This approach prevents thermal bridges and ensures an even layer of insulation across the entire roof. You retain internal space, and the roof is often sealed immediately. This significantly increases the energy efficiency of your home.
Although the costs are higher than with internal insulation, this method also provides greater comfort and savings.
Roof insulation costs
The costs depend heavily on the chosen method and the condition of the current roof. An indication:
Interior: €20 – €50 per m²
Exterior: €70 – €100 per m²
For an 80 m² roof, that means an investment between €1,600 and €8,000. Thanks to the subsidy, you can recoup a significant portion of that amount. Moreover, good roof insulation saves you hundreds of euros annually on your energy bill.
Flat roof insulation
For flat roofs, external insulation is usually the best option. This method, known as a "warm roof," keeps the load-bearing structure warm, thus limiting temperature fluctuations.
The insulation material is placed on top of the existing roof structure and then covered with a new waterproof layer. This extends the roof's lifespan and prevents moisture problems from within.
Insulation on the inside of a flat roof, a "cold roof," is rarely used. This increases the risk of condensation, which can cause roof damage.
Sloping roof insulation
You can insulate a sloped roof both inside and out. The choice depends primarily on the roof's condition and your budget.
Interior: fast and inexpensive, but you sacrifice some space.
Exterior: higher investment, but better insulation value and more comfort.
When planning a roof renovation, insulating the exterior is almost always worthwhile. You combine two measures in one and maximize your subsidy and energy savings.
Wondering if your home is suitable for roof insulation?
Wondering if your home is suitable for roof insulation?
Unsure if your roof is suitable for interior or exterior insulation? Have it checked with no obligation. Request a free roof inspection today from a specialist at Smienk Dakwerken. This way, you'll know exactly what's possible, what it costs, and how much you can save.
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