Reflective foil for radiators: So much energy can be saved

thermal insulation
Reflective foils for radiators: how useful is the attachment?

Many radiators are found on the outside walls and near windows, so that a large part of the heat generated is lost – with poor insulation. In order to reduce the resulting (high) energy costs, more and more households are turning to reflective foils. But do they really help?

Reflective foils for radiators are thin insulating panels that are usually coated with aluminum on one side. This should reflect the heat radiated to the rear back into the room instead of being lost via poorly insulated outer walls (as is often the case in old buildings). However, the question arises as to how effective the attachment really is. And do reflective films possibly pose certain risks? We’ll tell you.

This is what you need to know about reflective tape

Basically, the thicker a radiator reflective foil is, the better the insulation should be – but of course the price also increases with increasing thickness. Depending on the manufacturer, this often starts with three millimeters on, but there are also insulation mats that are between four millimeters and six millimeters or even up to 25 millimeters are fat. And that’s not the only difference: reflective foils can either be attached with an adhesive tape (or e.g. a Installation glue) can be fixed to the wall or they are self-adhesive. But we come to the crucial question of how sensible it really is to attach an insulating mat behind the radiator?

The good news is: insulating mats have an insulating effect and should therefore be able to reduce heating costs. The bad news is: according to experts, the savings are just between 1.5 and 4 percent. And that only if there is poor external insulation (i.e. in old buildings). As a result, heat is lost through the facade. This means: In modern new buildings, no noticeable change in the energy cost billing is to be expected from the attachment of a reflective foil. The assembly can therefore be useful, but only produces a small effect.

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How to attach the reflective foil correctly

Normally, reflective foils are supplied as a roll, regardless of whether these self-adhesive are or not. However, thin insulating mats can also be folded – that depends on the respective thickness and the manufacturer. But back to installation: In order for the film to achieve its full effect, you must ensure that the aluminum-coated side always faces the radiator – this is the only way the heat can be reflected back into the room. You should also pay attention to the following points:

And another tip: Bring them reflective foil always in pairs, then the assembly is much easier by hand – one:r holds the insulation mat and the other smooths the foil to remove all air bubbles. In this way, the film does not slip during installation.

Avoid mold formation: How to do it

Was the reflective foil Improperly fastened behind a radiator, moisture can form between the wall and the insulation – and thus promote mold. To avoid this, you can take preventive measures during installation: For example, if the panels are self-adhesive, you should always make sure that there are no gaps between the wall and the foil. Here can an ordinary paint roller (preferably with a telescopic rod) help to press the film evenly. Insulation panels, on the other hand, which are not glued on, should always have a flush connection to the wall. If you cannot attach the reflective foil flush, it is definitely helpful to dismantle the radiator beforehand. Although this involves more effort, it ensures a seamless result.

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