Wool protection

A decision for the right kind of insulation relies on certain criteria. Furthermore, durability of the insulation material is extremely important, because after all, insulation is a permanent installation and replacing it is not only time-consuming and nerve-wracking, but can also turn out to be quite expensive.

Therefore, a functioning, durable and healthy wool protection that keeps moths and carpet beetles away, is an important aspect when choosing sheep wool insulation.

Why is wool protection important?

Good wool protection is indispensable, because when moths and other wool pests first take up residence in sheep's wool insulation, great damage is caused, not to mention that the small moths and their larvae are very difficult to get rid of again.

The following two questions explain why sheep’s wool is an indispensable matter within this context:

  1. What exactly is sheep's wool?

    Sheep's wool is a natural animal fibre. It mainly consists of proteins. The basic protein building block is keratin, which also makes up our hair and nails.

  2. Why is sheep's wool interesting for moths?

    The larvae of the clothes moth or the carpet beetle need the protein keratin contained in the wool fibres to grow. They prefer a quiet, dark environment. A carpet that is constantly walked on in a bright living room is therefore of little interest to the clothes moth. Of course, the situation is completely different with insulation installed in the wall.
Unscrupulous competition
Unfortunate example: Moth horror in Switzerland

In January 2021, a tragic renovation case became known via SRF (Swiss Radio and Television). A family from Basel renovated an old, listed house. For the sake of the environment, the old glass wool was replaced by natural sheep's wool.

Before installing the insulation, the dealer promised the family that the wool had been treated against moths and larvae. Unfortunately, there was nothing in writing about this. Gradually, the family began to notice that all the wool was full of moths and larvae.

SRF's legal expert advised that it is essential to obtain certificates and a written assurance - we fully agree with this!

Always request the certificates including the certificate number to be on the safe side. Get at least three certificates:

  • The certificate of the long-term test according to EAD
  • The active ingredient name of the agent used and the corresponding biocide authorisation.
  • A certificate of harmlessness for people and nature, such as the natureplus certification

By the way, here is our proof →

We strongly condemn cases like the one described above and consider the sale of such "insulation materials" unacceptable.

A bad story followed by good news

You don't have to give up the many advantages of healthy and natural sheep's wool insulation for fear of moths.

With the right wool protection, you are 100% safe from moth horror. Our patented, biocide-free IONIC PROTECT® process provides wool protection that we guarantee.

Auf die schlechte Geschichte folgt sogleich die gute Nachricht


Du musst aus Angst vor Motten, aber keineswegs auf die vielen Vorteile der gesunden und natürlichen Schafwolldämmung verzichten.

Denn mit dem richtigen Wollschutz bist du zu 100% vor Motten-Horror gefeit. Unser patentiertes, biozidfreies IONIC PROTECT® Verfahren sorgt für einen Wollschutz, mit dem wir dir das garantieren.

The natural IONIC PROTECT® wool protection 

Wool protection has always been an important, if not the most important aspect for us in the production of sheep wool insulation.

Trademark patent

We have developed and tested the IONIC PROTECT® process over many years and have also protected it under trademark patent law. It is a plasma ion treatment of the wool fibres with the aim of protecting them from all negative influences that can occur in construction. 

Modification of the fibre

In the process the fibre surface is modified without the addition of biocides so that the wool is permanently protected from all negative influences. This is continuously checked and certified.

Biocide-free protection

Among other things, this means that our wool is simply no longer tasty to moths and is therefore protected against feeding and permanently biocide-free.

Durable protection

This unique treatment method is only carried out by ISOLENA and gives the sheep's wool all the properties that are necessary for its durable function as an insulating material. The functionality has been tested and confirmed in the laboratory (EAD/CUAP).
In detail: How IONIC PROTECT® works

In the IONIC PROTECT® process we use plasma instead of chemicals to permanently change the fibre surface of the wool. In this way, we also achieve permanent wool protection.

The plasma we are talking about here is not to be confused with medical plasma (= blood plasma), which is liquid, cell-free blood

To understand what happens with our plasma ion treatment IONIC PROTECT®, let's take a short detour into physics.

What is plasma?

  • Plasma is a fourth state of aggregation after solid, liquid and gas.
  • The plasma state can be achieved by changing a gas by adding energy (= ionisation).
  • Plasma is therefore gas in a higher-energy state. This means that plasma matter has a high proportion of free ions and electrons.

Natural phenomena such as lightning, auroras or the solar wind are plasma states. You see, glow is (in most cases) one of the characteristics of plasma. The most important property for us, however, is electrical conductivity. 

What is ionisation?

  • Ionisation is a process in which one or more electrons are released from a molecule or an atom.
  • The atom or molecule remains as a positively charged ion.

  • After ionisation, there are therefore many free electrons in the plasma, which is the cause of the high-energy state of the plasma.

The term 'ion' comes from the ancient Greek ἰόν or ión, which means 'the leaving'. So the name says it all: an ion is created when an electron 'leaves' an atom.


What does IONIC PROTECT® do?

  • The sheep's wool passes through a machine in which a high-energy plasma field is generated.

  • Electrons and ions interact with the wool and change the molecular structure of the wool fibre.

  • After this treatment, the wool fibre is no longer edible for keratin-eating insects such as moths or carpet beetles.

To monitor and ensure the product safety and quality of each batch of wool, all processes except wool collection and wool washing are carried out in-house. The process is long-term tested so we can guarantee that no moth infestation can occur even after many years.

What other wool protection is there?

Wool protection through addition of other fibres

In order to make sheep's wool less attractive to pests, there are manufacturers who mix wool with synthetic fibres or PLA fibres. However, this also means that the positive properties of wool are lost, and, in our opinion, one can no longer speak of a natural product.

In the sheep's wool insulation industry, ISOLENA is known as an innovative "hardliner" that checks and then sets the standards in quality. Mixing virgin sheep's wool fibres with synthetic or PLA fibres is not an option in the insulation material from our point of view.

Wool protection by "finishing" the sheep's wool

Another way is the so-called "finishing" of the insulation material. This is a treatment of the sheep's wool that changes certain properties of the raw material wool. In this case, the finishing aims to protect against pests.

One commonly hears or reads about  different active substances with which sheep's wool is equipped against moths. The most important of these we explain here.

Borates / boric salt

Boric salt was one of the first agents used on sheep's wool against insect damage. The active ingredient kills eggs, larvae and insects, but unfortunately is also extremely toxic.

Sheep's wool treated with boric salt also partly provides fire protection, but the agent is not approved as an active ingredient against insect infestation.

Despite the initial effect of the poison, there was still repeated damage as the boric salt volatilises over time and thus offers no lasting protection against moths and insects.

Neem oil

Neem oil, also known as margosa oil, is extracted from the seeds of the neem tree, which is native to Asia. The active ingredient azadirachtin is the magic ingredient that keeps pests from eating away plants or fabrics.

The good thing about neem oil is that it only harms the pests. The bad thing about its use in insulation materials is that the active ingredient does not have the long-term effect required for an approved building material and subsequent treatment is not possible for installed insulation materials.

Products treated with neem oil unfortunately offer no protection against moth infestation.

Thorlan IW

Thorlan IW was a chemical, permanently effective wool protection from the Thor company.

The proven active ingredient was tested by natureplus, classified as harmless and approved as part of the natureplus certification. One of the reasons for this is that Thorlan forms a permanent bond with the virgin sheep's wool, so there is no emission into the indoor air.

For economic reasons, Thor GmbH has not renewed the EU approval as a wool protection, which is why Thorlan IW is no longer available.

Mitin or Sulcoforon

Sulcoforon is a substance that was used in products called "Mitin". The active ingredient is an organic halogen compound and poses a health hazard. For genuine, ecological building materials, finishing with mitin was therefore never an option.

For these reasons, mitin has been banned in the EU since 2006. There should therefore no longer be any EU manufacturer offering sheep's wool insulation with this finish.


Permethrin is a synthetic insecticide. It is used as a contact and feeding poison and has a very broad spectrum of action. In contrast to Thorlan IW, however, the active ingredient is not permanently bound.

This is how wool protection with the biocide permethrin works:

  • For sheep wool insulation to be protected against moths by permethrin, the insulation material is treated with the pesticide during or at the end of the manufacturing process.
  • Insects like the textile moth or the carpet beetle absorb the nerve poison, are paralysed and die after some time.
  • Even when the active ingredient fades, the lethal effect on the insects is usually still very good. However, if this fades, it could lead to the toxic dose no longer being sufficient for death. The pests are then only briefly stunned and will recover after some time.
  • The active ingredient does not really disappear quickly. The development of the concentration of the active substance was checked in several experiments. Thus, a long-lasting exposure of indoor spaces to the active ingredient was found. Bad for the moth, good for the toxic effect. Unfortunately, however, in humans - depending on the type of contact with the active ingredient - there can also be complaints, even though these are classified as harmless by the EU.

Unfortunately, for lack of alternatives, many sheep wool insulation manufacturers use permethrin as a wool preservative.

To what extent one still wants to consider sheep wool insulation as natural and healthy after such a pesticide treatment, is something everyone must decide for themselves. In any case, the use of the nerve agent is not permitted for natureplus products.


For further reading:

There are many research reports conducted by NGOs such as Greenpeace that deal with the effects of chemicals and pesticides. Here are two examples that also deal with permethrin (from the group of pyrethroids), among other things:


Wool protection - Our conclusion

Our company, now in its third generation, has been working and processing virgin sheep's wool in Austria for more than 50 years. The approach to all our products is to process them according to the highest quality standards, without synthetic additives.

We have been striving for a long time and with passion to establish the insulating material made of virgin sheep's wool with its extraordinary properties in the insulation sector. Therefore, biocide-free wool protection is of primary focus for us.

We are very proud to have developed a permanently effective protection against moths with our unique IONIC PROTECT process. This gives us the opportunity to produce and offer natural sheep wool insulation at a high quality level.

Be thorough when choosing the manufacturer, because unfortunately there are also black sheep in our industry from which we set ourselves apart.