Sheep's wool insulation

Natural insulation material with many talents:

Sheep's wool is the only naturally occurring insulating material that keeps you warm and protects you from heat, cold and moisture. The uniqueness of the raw fibre sheep's wool also makes it a material with unique advantages in its end product.



Sheep's wool has the best insulation values

Thermal conductivity is one of the most important insulation values for assessing the effect of insulation materials. It is measured in W/mK (watts per metre and kelvin) and is also known as the lambda value (λtr). The thermal conductivity indicates the amount of heat that passes through the building material.

For a material to act as an insulator, it should have a value below 0.1 W/mK. The rule is that the smaller the thermal conductivity, the better. ISOLENA sheep's wool insulation has a very good insulation value of 0.034 - 0 .042 W/mK.

The actual thermal conductivity is calculated from the combination of materials used. Wood, for example, has a good thermal conductivity value and thus 'helps' other materials with thermal insulation.


Sheep's wool purifies the indoor air

Sheep's wool naturally creates a healthy indoor climate and thus promotes your health. Our ISOLENA sheep's wool is demonstrably able to break down pollutants and odours, as shown in the measurement below from the German Wool Research Institute:

Minimisation of indoor pollutants using the example of formaldehyde.

The secret behind this excellent ability is keratin, the basic protein building block that makes up sheep's wool. The molecules of the amino acid side branches can absorb pollutants such as formaldehyde and neutralise them. This results in a chemical reaction, whereby the pollutants are bound to these molecules or converted.

The closer sheep's wool is installed to the interior, the better the positive effect on the indoor climate. For example, installation levels, partition walls and false ceilings with sheep's wool insulation have a great effect on the indoor air.

Sheep's wool under the microscope
No fibre contamination No fibre contamination
No fibre contamination of the room air

Sheep wool provides the necessary security. Due to the spinning technology,
ISOLENA products contain sheep wool fibres with a minimum length of approx. 20 mm.

Since the fleece rolls are cut at the side edges for assembly, it is possible that shorter fibres occur and that these come loose during assembly activities. When installed, no more fibres come out and thus, fibre contamination of the room air can be ruled out.


Sheep's wool regulates moisture

Sheep's wool has a hygroscopic effect, i.e., it binds moisture when the air humidity is higher than the compensating humidity of the wool. If the room air is too dry, it releases the moisture again.

Sheep's wool can absorb up to 33% of its own weight in moisture without losing its insulating properties, without becoming damp. It also retains its bulkiness without having a damaging effect on the building fabric.

The reason for this is the unique structure of the protein fibre: it is water-resistant, i.e., hydrophobic. A property that is very advantageous, for example, for installation environments with high condensation.

Another natural advantage of protein fibre is that it does not provide a breeding ground for mould. Therefore, sheep's wool is naturally protected against mould.


Fire protection with sheep wool Fire protection with sheep wool

Sheep wool insulation with fire protection

Due to the consistent use of 100% virgin sheep's wool, the special ISOLENA processing technology and the innovative, biocide-free wool protection IONIC PROTECT®, our sheep's wool insulation achieves – depending on product and construction – fire classification of B1, C or D according to EN 13 501-1.

The natural fibre of sheep's wool has a self-ignition temperature of 560 – 600° C. This is about twice as high as wood (270° C). It shrivels away from any heat source without the material melting.

ETA Prüfbericht ETA Prüfbericht
Degradation of toxic gases. (Quelle: Benisek Phillips, J. Fire Science, Issue 1 Nov/Dec 1983)

The fire behaviour always depends on the entire construction. ISOLENA is so far the only natural insulation material that achieves fire classification B1 with the following acoustic ceiling element:

  • Perforated plasterboard panel,
    thickness 12 mm, perforation Ø 18/18 – 5 mm
  • ISOLENA Optimal, thickness 40 mm,
    density 18 kg/m3, 60 mm back ventilation

Compliant with Austrian standard EN 13501-1, the construction product described is classified B s1, d0 with regard to its fire behaviour. 


Effective sound insulation

Due to a different fibre fineness, sheep's wool has very good sound absorption properties for many acoustic situations with higher vocal demands.

You can equip acoustic ceilings with special ISOLENA acoustic tiles or simply with ISOLENA sheep's wool felts.

For good reason, our acoustic products are increasingly being used by architects, civil engineers and builders for kindergartens and schools, office buildings, function rooms, as well as in private homes.


Sheep's wool is a renewable raw material

Our goal at Lehner Wool has always been to use the natural properties of our sustainable raw material sheep’s wool and to demonstrate its positive effects.

Sheep's wool insulation represents the insulation material of the present and future for environmentally conscious and ecologically minded people. Only wool from live sheep is suitable to produce insulation materials with such high quality standards.

Furthermore, only sheep’s wool is and remains the permanently elastic, bulky and lively material that it needs to be to fulfil its many tasks as an insulating material.


Lehner's Wool-Lifecyle:
  1. We purchase our sheep wool from partners who care about ecological criteria.
  2. Sheep must be sheared according to animal welfare laws, depending on the breed 1-2 x / year.
  3. The valuable raw material sheep wool is washed naturally with soda and curd soap.
  4. We produce sustainable products from the virgin sheep's wool: from yarns and felts to carpets, acoustic products and insulating materials.
  5. Our high-quality products are all characterized by longevity and are used for generations.
  6. Sheep's wool is the only natural insulation material that integrates 100 % into the natural cycle and is completely compostable.
Wool Lifecycle Wool Lifecycle

Resistant to moths thanks to IONIC PROTECT®

IONIC PROTECT® is a biocide-free process developed by ISOLENA and protected by a trademark patent to protect wool from all wool pests.

Plasma ion treatment of the wool fibres protects them from all negative influences that can occur in construction. This gives moths and insects no chance to thrive. In addition, our products can be stored indefinitely thanks to the wool protection.

We present you with these terms in writing with the ECO/CUAP test report ECO-P16002-15017 and our product promise.

You can find more information about wool protection in our magazine article "Durable wool protection". 


Mit Betätigen des Play-Buttons, wird der externe Dienst YouTube gestartet. Pressing the play button starts the external YouTube service.

Sheep wool insulation is easy to process

Our ISOLENA sheep's wool insulation is delivered ready-made to size. This makes it easy for you to process.

You don't need a dust mask or protective clothing, because the sheep's wool is very kind to your skin and health during further processing.

Cutting to length is very simple by hand or with the ISOLENA cutting device.

Mit Betätigen des Play-Buttons, wird der externe Dienst YouTube gestartet. Pressing the play button starts the external YouTube service.

Certified wool origin and processing

Our sheep's wool comes directly from nature, more precisely from sheep in Central Europe.

All ISOLENA products bear the nature plus® test mark for sustainable building materials, which stands for health compatibility, environmentally friendly production, conservation of finite resources and fitness for purpose.

Demanding tests and the strictest limit values for substances that are hazardous to health throughout Europe guarantee the harmlessness of the certified products.


CO₂ savings with sheep's wool

 In times of global climate change with massive effects also on the building industry, we want to show the CO2 saving potential directly in the application. Our approach:

  1. A comparison of insulation materials for a house with 60 m³ of insulation area was carried out.
  2. The comparison takes place at the level of the same functional unit (FE), in this case thermal resistance.
  3. The conversation factor on 1 kg is calculated by multiplying the gross density, thermal conductivity, thermal resistance and area: ρ[kg/m³] * λ[W/mK] * R0[m²K/W] * A0[m²] with R0 = 1 m²K/W and A0 = 1[m²].
  4. As a result of averaging on the basis of production quantities, the average raw density for ISOLENA insulation materials is 18 kg/m³.

The remarkable result of this comparison: using one tonne of ISOLENA sheep's wool insulation can save more than 1.6 tonnes of CO₂ compared to conventional insulation materials.


CO2 Vergleich Schafwolle CO2 Vergleich Schafwolle
CO₂ comparison
  100% sheep wool ISOLENA
18 kg/m³ – 0 ,038 W/(mK)
Natureplus® balance
Glass wool
18 kg/m³ – 0 ,038 W/(mK)
Value from „baubook“
Rock wool
28 kg/m³ – 0,044 W/(mK)
Value from „baubook“
Global warming potential
GWP total [CO2 eq.]
incl. CO2 storage
0,83 / kg
0,57 / FU
2,45 / kg
1,68 / FU
1,93 / kg
2,38 / FU
House with 60 m³ insulation area
1 t sheep wool
equivalent to 1 t glass wool
equivalent to 1,59 t rock wool
830 kg CO2 2450 kg CO2 3069 kg CO2
CO2 savings
with the use of sheep’s wool
  1,62 t 2,24 t


You will be well-received by the following advisers:

Helga Haslehner
Sales Manager
+43 7277 2496-302

Catalin-Andrei Farcas
Key Account Manager
+43 7277 2496-300

Christian Radlmair
Sales Manager
+43 7277 2496-303