Dam blinds: how does that work?


What has to be insulated in the roller shutter, and why, is for many a technical mystery. Find out here which parts need to be insulated for which reasons, and where this is even required by law. In addition, this article reveals the efficiency of such insulation.

Ban on thermal bridges

The EnEV, the current Energy Saving Ordinance, like all the technical rules for building and renovation clearly states that thermal bridges must always be avoided.

What is a thermal bridge?

Technically, a thermal bridge becomes a location or component within an outer wall where the thermal transmittance value is significantly higher than that of the surrounding components. Colloquially (and because it is more logical) you often hear the expression "cold bridge". But that means the same phenomenon.

The technical rules require that all adjacent or contiguous components have similar heat transfer coefficients as possible. This is indispensable for the planning of the insulation and the correct execution.

What can thermal bridges do?

A thermal bridge causes a thermal disturbance in the component with the higher thermal transmittance. That is, where poorer insulated, creates a cold spot. It creates condensation, which can lead to mold and moisture.

In addition, the dew point is shifted into the wall, which can lead to additional moisture of the walls.

When is a roller shutter box a thermal bridge?

Simple answer: whenever it is not sufficiently insulated. The same applies if a roller shutter box is leaking. Then the thermal bridge is even more serious.

That's easy to test with a candle. If a candle held in the roller shutter box flickers, there is a leak. In the same way you can also test the webbing.

Detailed information is provided by a thermographic analysis using a thermal imaging camera. Here also different U-values ​​of wall and roller shutter box are clearly visible. In this case, the roller shutter box must necessarily be subsequently insulated.

Funding for the insulation of the shutter box

The funding programs of KfW can help to finance some of the costs of insulation. In most cases KfW's program no. 430 is applicable here, where a subsidy of 10% of the eligible costs (maximum EUR 5,000) can be obtained.

In the case of a comprehensive energy-saving refurbishment of the entire building, the insulation or replacement of the roller shutter box can also be taken into account in other possible subsidy programs.

Insulation of the roller shutter

Some manufacturers offer special, foamed aluminum roller shutter armor, which is supposed to have better thermal insulation.

More important, however, is the highest possible airtightness between the roller shutter armor and the window. The more air exchange takes place there, the greater the heat losses. The material of the tank is comparatively negligible when it comes to the heat-retaining effect.

The reduction of columns and the complete closing of the shutter (let down completely) are clearly more important.


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