Would you like to find out more about sustainable thermal insulation and ecological insulation materials? Then you've come to the right place! The sustainability of buildings is not only determined by their energy efficiency in everyday use, but also by the choice of material. Accordingly, many people are looking for green alternatives to conventional insulation materials such as foam glass, glass wool or extruded polystyrene. But can these really be sustainably replaced with similar thermal conductivity and comparable fire and sound insulation properties?
In this article, I would like to give you everything you need to know about sustainable thermal insulation. You'll find out why it's so important, what to look out for and which natural insulation materials are suitable for which area of application. Let's go!
You can find a brief overview of the materials here in advance:
Advantages: Why is sustainable thermal insulation so important?
The main task of thermal insulation is to make interior spaces protect against heat and coldthrough higher energy efficiency Save heating costs, maintain or even increase the value of the building - and the Increase living comfort. Due to the all-encompassing, Energy-efficient refurbishment of a building the primary energy demand can actually be reduced by up to 90 percent.₁
First of all, any reasonably effective thermal insulation material saves significantly more energy over its entire service life than is required to manufacture it. As a rule, the production of any insulating material is always better for the environment than doing without insulation altogether.₂
So every insulation material is worthwhile - also from an environmental point of view! So why now an alternative that is as close to nature as possible to mineral and synthetic insulation materials such as rigid polyurethane foam, vacuum insulation boards or glass wool?
The advantages of natural insulating materials
Here I present the most important advantages of sustainable insulation:
- Conserve resources: Ecological insulation materials are made from renewable raw materials or recycled materials and therefore protect the environment. natural resourcesthat the earth makes available to us.
- Subsidies: Some cities (e.g. Düsseldorf, Hamburg, Hanover, Münster and Munich) subsidize the use of certified natural insulation materials with special support programs from which consumers can benefit.
- More living comfort: The main advantages of insulating with natural materials also include a more pleasant indoor climate and less susceptibility to mold growth.
- Lower energy consumption during production: Natural insulation materials can be produced with significantly lower energy consumption. Production is generally more climate-friendly than that of conventional alternatives.
- Easier recycling: At some point, every insulation material has to be replaced. Fortunately, natural insulation materials can be recycled very easily or burned to generate energy.
Material: 11 ecological insulation materials for sustainable thermal insulation
Now we can confidently move on to the ecological materials that can generally be used as insulation. I will provide you with valuable information on each of them, including Heat insulation, thermal insulation effect, thermal conductivity, moisture equalization, fire protection and sound insulation with the hand.
You will also find out for which Application area the insulation materials are suitable₃ - because whether you have a Thermal insulation from the inside or outside, or whether you want to insulate the roof or the cellar wall, is ultimately decisive for the right choice of material.
1. wood fiber
The wood fiber insulation boards are from debarked residual wood The resin means that no adhesive is required. They have a good moisture balance, are an ideal heat insulator in summer, protect well against noise and achieve good thermal insulation. Soft wood fibers are suitable for insulation measures on flat roofs, exterior and interior facades, trowel corners and top floor ceilings.
Here are important facts for insulation with wood fiber boards at a glance:
- Bulk density: 110 to 600 kg/m3
- Thermal conductivity: 0.040 to 0.083 W/(mK)
- Resistance number water vapor diffusion: 3 to 5
- Fire class: B1, B2
- Temperature resistance: 110 degrees Celsius
- Cost: 16 - 45 euros per square meter
2. cork
Another sustainable alternative to conventional insulating materials is cork - either as an insulating board or loose for pouring. Cork is obtained from the bark of the cork oak, offers excellent sound insulation and also scores well in terms of heat insulation and moisture balance. Fire protection and thermal insulation are still mediocre - and long transportation routes are also necessary.
You can use the pressure-resistant material for the Cavity insulation or for external roof and facade insulation.
Here are important facts for insulation with cork panels at a glance:
- Bulk density: 100 to 220 kg/m3
- Thermal conductivity: 0.040 to 0.060 W/(mK)
- Resistance number water vapor diffusion: 5 to 10
- Fire class: B2
- Temperature resistance: 110 to 120 degrees Celsius
- Cost: 7 - 60 euros per square meter
3. straw
Straw can also be used to insulate walls sustainably - it is used, for example in the form of straw building boards or used as a lightweight aggregate in clay products. The ecological insulating material straw can be produced with extremely low energy consumption and has a good thermal insulation effect. It also serves as heat insulation and effective soundproofing.
The material can be used to insulate roofs, exterior walls and floors in particular.
Here are important facts for insulation with straw at a glance:
- Bulk density: 85 - 115 kg/m3
- Thermal conductivity: 0.043 to 0.052 W/(mK)
- Moisture balance: average to good
- Fire class: B2
- Cost: about 48 euros per cubic meter
4. wood wool
Anyone interested in natural, sustainable thermal insulation should also take a look at wood wool. It is one of the most popular, near-natural insulation materials and is made from the long-fibered chips of spruce or pine wood. It is a flame-retardant insulating material that protects interiors well against heat and also acts as effective sound insulation.
As the thermal insulation effect of the material is not quite as good, wood wool lightweight boards can be used to insulate top storey ceilings in particular, but also interior facades and cellar ceilings.
Here are important facts for insulation with wood wool at a glance:
- Bulk density: 110 to 600 kg/m3
- Thermal conductivity: 0.040 to 0.083 W/(mK)
- Resistance number water vapor diffusion: 3 to 5
- Fire class: B1, B2
- Temperature resistance: 110 degrees Celsius
- Cost: 7 - 20 euros per square meter
5. hemp
From the stalks of the hemp plant an ecological insulating material with excellent thermal insulation properties can be obtained using a crushing and forestry process. Hemp fibers also score highly in terms of fire protection, moisture compensation and heat protection.
Pitched and flat roofs, upper floor ceilings, interior and exterior façades, as well as basement ceilings, are possible areas of application.
Here are important facts for insulation with hemp at a glance:
- Bulk density: 40 to 50 kg/m3 (stuffing wool); 20 to 40 kg/m3 (mats)
- Thermal conductivity: 0.040 to 0.080 W/(mK)
- Resistance number water vapor diffusion: 1 to 2
- Fire class: B2
- Temperature resistance: 100 degrees Celsius
- Cost: 10 - 30 euros per square meter
6. meadow grass
Another insulation material that is green in the truest sense of the word is natural meadow grass. The renewable raw material is available as blown-in and loose-fill insulation and is particularly environmentally friendly due to its regional availability. The meadow grass insulation material is moisture-regulating, thermally insulating and also provides good protection against the summer heat.
The material is particularly suitable for insulating cavities in walls, floors and roofs - and is therefore often used in the renovation of older existing buildings.
Here are important facts for insulation with meadow grass at a glance:
- Bulk density: 40 to 65 kg/m3
- Thermal conductivity: 0.039 and 0.046 W/(mK)
- Fire class: B2
- Cost: 52 - 107 euros per square meter
7. jute
Environmentally friendly thermal insulation also works with a jute fleece! To produce the insulating material, you recycle old jute sacks. Even though jute provides little protection against sound, it still has a great thermal insulation effect and at the same time serves to protect against heat and equalize moisture. The fabric is natural, free from harmful substances and available at a reasonable price.
The jute mats and rolls are ideal for thermal insulation of the roof - for example as insulation between or under rafters. They can also be used to insulate flat roofs, external and internal facades and cellar ceilings.
Here are important facts for insulation with jute at a glance:
- Bulk density: 30 - 50 kg/m3
- Thermal conductivity: 0.037 and 0.040 W/(mK)
- Fire class: B2
- Cost: 2.20 - 2.70 euros per square meter
8. reed
Another absolutely ecological insulating material is reed. Biodegradable reeds are pressed together to form panels. They create an ideal moisture balance and prevent rotting and mold growth, for example. They also work well as heat and sound insulation.
In fact, buildings can be insulated with reed in many different ways. For example, as on-roof insulation (the most efficient external roof insulation), for floor insulation or as a thermal insulation system in the walls.
Here are important facts for insulation with reed at a glance:
- Bulk density: 190 - 225 kg/m3
- Thermal conductivity: 0.038 - 0.055 W/(mK)
- Fire class: B2
- Cost: 10 - 20 euros per square meter
9. flax
The following is also suitable for sustainable thermal insulation Waste product of linen productionFlax. In mat and fleece form or as bulk material and stuffing wool, this natural material has an excellent thermal insulation effect. It is also very well suited as an environmentally friendly natural insulating material due to its sound-insulating, moisture-balancing and heat-protecting properties.
You can use the flax insulation boards for finishing walls, ceilings and roofs or even the floor, for example. Flax stuffing wool, on the other hand, is very suitable for sealing doors and windows.
Here are important facts for insulation with flax at a glance:
- Bulk density: 40 to 50 kg/m3 (stuffing wool); 20 to 40 kg/m3 (mats)
- Thermal conductivity: 0.040 to 0.080 W/(mK)
- Resistance number water vapor diffusion: 1 to 2
- Fire class: B2
- Temperature resistance: 100 degrees Celsius
- Cost: 5 - 50 euros per square meter
10. cellulose
Cellulose is obtained through the recycling of waste paper. Because cellulose is biodegradable, cheap and regionally available, insulates heat very well and also protects well against heat, sound and the usual risks of moisture, it is one of the most widely used ecological insulating materials.
You can use the insulation material to insulate roofs or partition walls, for example. It is just as suitable as façade insulation for buildings with Timber frame construction.
Here are important facts for insulation with cellulose at a glance:
- Bulk density: 30 to 60 kg/m3
- Thermal conductivity: 0.039 to 0.045 W/(mK)
- Resistance number water vapor diffusion: 1 to 2
- Fire class: B2
- Temperature resistance: 60 degrees Celsius
- Cost: 10 - 38 euros per square meter
11. seaweed
Anyone who finds out about sustainable building insulation will inevitably hear about the somewhat more modern seagrass thermal insulation. The washed up Balls made from seagrass plant fibers offer excellent moisture equalization and also have a good thermal insulation effect. They also provide good heat and sound insulation.
Seagrass is ideally suited for insulating interior and exterior facades, an uninsulated top storey ceiling, for insulating the roof between the rafters and for insulating wooden beams.
Here are important facts for insulation with seagrass at a glance:
- Bulk density: 65 to 75 kg/m3
- Thermal conductivity: 0.039 to 0.046 W/(mK)
- Fire class: B2
- Cost: 27 - 57 euros per square meter
Notice: There are certainly other natural insulating materials, such as sheep's wool. For ethical reasons, however, I do not wish to discuss them further here. In addition to the animal welfare aspect, the susceptibility to destruction by moths also speaks against using sheep's wool to insulate buildings.
Sustainable thermal insulation pays off!
And not just for your wallet and your well-being, but also for the environment. By investing in one of these ecological insulation materials, you are not only helping to increase the energy efficiency of buildings in Germany - you are also saving energy during production, conserves natural resources and facilitate recycling.
However you use the knowledge from this article: I hope that I have been able to help you achieve more environmentally friendly insulation with this information.
Do you have any questions, tips or your own experiences with energy-efficient, sustainable thermal insulation that you would like to share? Then I look forward to your comment.
Stay sustainable,
PS: Do you already know how to build sustainably can? In the linked article you will now learn the most important tips for this!
References:
₁,₂ Federal Environment Agency: Thermal insulation questions and answers (as at: March 2016), available at https://www.umweltbundesamt.de/sites/default/files/medien/376/publikationen/waermedaemmung_fragen_und_antworten_web.pdf. [14.12.2022].
₃ N. Paul (2015), Ökologische Dämmstoffe, available at https://benz24.de/media/landingpages/ratgeber/ebook/oekologisch_daemmen/leitfaden-ratgeber-oekologische-daemmstoffe.pdf. [14.12.2022].
