Read more 10 reasons

Close-up Supafil Knauf Insulation Blowing Wool Product
The top 10 advantages of glass mineral blowing wool

REASON 1 - Blown mineral wool meets all eight requirements of good insulation


SUPAFIL®  offers outstanding performances in all eight requirements of good insulation. Those are:

  • thermal

  • acoustic

  • fire protection

  • health

  • comfort

  • buildability

  • durability

  • sustainability.  

REASON 2 - Knauf Insulation SUPAFIL® blown mineral wool sets industry standards

Supafil Installer Hokkaido Japan Knauf Insulation Blowing Wool

Easy to install
Offers high covering performance, reduced handling and a quick installation that does not disturb building users. With Knauf Insulation, installers have a dedicated range of easy-to-install products and can enjoy added value services such as technically advanced blowing and carding machines and the KI Spot Protector accessory for the reliable insulation of recessed spaces+D7

Remains stable
Shows very little settlement over time and is classified S1

Made from recycled glass and quarry sand (not seabed sand) SUPAFIL is 100% recyclable

Classified A1 for reaction to fire and does not show any propensity for continuous smouldering combustion

Water repellant and rot-proof
Resistant to fungi, microbes, mould and degradation. Will not absorb and retain moisture and deters  rodents and insects without any product treatment

Safe for your health
Contains no dangerous substances such as boric acid or added formaldehyde

Comfortable installation
Generates very little amount of dust 

REASON 3 - SUPAFIL® can be used for a range of applications

3D Insulated House Model Details

SUPAFIL® Blowing Wool is suitable for multiple applications:

  • Loft spaces, particularly those that are difficult to access, in both residential and non-residential buildings

  • For insulating cavity walls, particularly during renovation

  • For thermal and acoustic insulation of car parks

REASON 4 - SUPAFIL® glass mineral wool is a better choice than organic insulation

Supafil Naked Wool

SUPAFIL® mineral wool has many distinct and compelling benefits vs organic insulation (e.g. wood fibres or cellulose):

  • It offers an array of solutions, allowing builders and homeowners to choose the best option at the right price for their construction budget.

  • It is safe to manufacture, install and use when recommended work practices are followed.

  • It will not absorb and retain moisture.

  • It has less than 1% of settlement when properly installed.

  • SUPAFIL® mineral wool is CE certified.

  • Mineral wool insulation materials are supported by 75 years of health and safety research that demonstrates they are the most thoroughly evaluated insulation materials on the market.

Organic insulation has several disadvantages compared to SUPAFIL® mineral blowing wool:

  • Unlike SUPAFIL®, organic insulation has chemical additives, which are applied to deal with fire hazards. Some of them need chemical additives (e.g. boric acids) to improve reaction to fire classification.

  • Organic insulation naturally absorbs and retains moisture. This can lead to mould growth, which is a health hazard.1

  • SUPAFIL® mineral wool has been rigorously tested for health hazards. The true health impacts of cellulose dust remain unclear and more scientific evidence is needed.2

  • Organic insulation insulation may contain boric acid, which are reprotoxic.3

There are two main advantages of glass mineral wool:

  • Glass mineral wool is 1.8 times lighter than rock mineral wool. This is an important consideration with respect to the weight on ceilings and maximum additional loads.

  • Rock mineral wool has a reputation for being abrasive which can damage blowing machines.

  • Rock mineral wool is denser than glass mineral wool and therefore takes longer to install.

1 Moisture absorption, ranging from 5-20% of its weight, is one disadvantage of cellulose insulation. Richard T. Bynum, Jr., Insulation Handbook (New York: McGraw-Hill, 2001), p 83.
2 Reach-dossier confirms the non-hazard level of the European CLP. Check also the Safety Datasheet for more information
3 ECHA, Inclusion of substances of very high concern in candidate llist, Helsinki, 17.06.; CLH report Proposal for Harmonised Classification and Labelling, Based on Regulation (EC) No 1272/2008 (CLP Regulation), Annex VI, Part 2

REASON 5 - SUPAFIL® offers superior water vapour resistance and thermal performance 

SUPAFIL Blowing Wool Scheme Drawing Coloroud Background

SUPAFIL® offers excellent resistance to water vapour absorption and thermal performance.

SUPAFIL® is significantly more resistant to water vapour absorption than organic insulations (e.g. wood fibres or cellulose):

  • Silicone additive on Supafil® products provides an efficient water barrier even under the harsh conditions of the test.

  • The higher levels of water vapour absorption with cellulose and wood fibres results in a significant reduction in thermal performance.

  • Subsequently the R-value reduces significantly from its original installed value.

REASON 6 - SUPAFIL® offers superior dust performance

Onnetsu Installer Spraying Supafil Loft Japan

For the same R-Value, Supafil® generates significantly lower levels of airborne dust than organic insulations (e.g. wood fibres or cellulose)*:

  • Organic insulation generates much more dust.

  • Installation of organic insulation was uncomfortable with the airborne dust causing poor visibility and poor air quality.

Safe for your health:

  • Mineral wool insulation products are supported by 75 years of health and safety research that demonstrates they are the most thoroughly evaluated insulation materials on the market.

* It has to be noted that the machine used for the tests was the same for all products (SE1000) and although settings were optimised for each product installation, the machine generally processes material more than other machines and could contribute to higher dust values seen with organic insulation

REASON 7 - SUPAFIL® is best for indoor air quality

Comparison of blowing wool with organic insulation:

SF Criteria Chart-cropped

Pan-European 'one-stop shop' to comply with EU regulations, voluntary product certification labels and building certification requirements:

  • IAC GOLD covers all Volatile Organic Compounds (VOC) parameters from regulations, product and building certifications.

  • For each VOC parameter, IAC GOLD includes the most stringent limits. 

  • IAC GOLD adopts the most stringent regulation, product and building certification updates.

EuroFins Chart-cropped

Organic insulation exhibits different Volatile Organic Compounds (VOC) emission patterns:

  • Cellulose – total quantity of VOC emitted is higher than the IAC GOLD criteria, together with formaldehyde release after 28 days*.

  • Wood fibres combine both high total VOC emissions and substances of concern that may exhibit health risks in case of long term exposure (R value ~ 5 to 8)*.

*Based on an internal analysis from 2019.

VOC emission pattern from cellulose & wood fibre is a consequence of their core material design and cannot be mitigated easily. 

SUPAFIL has the lowest VOC emission pattern by design < 1% organic content.  

REASON 8 - Knauf Insulation is at the cutting edge of assessing the performance of products like SUPAFIL® 

Regular and extensive Life Cycle Assessments (LCAs) are conducted to produce robust and up-to-date Environmental Product Declarations (EPDs).

GMW LCA diagram_sl17
EPD Poster

Knauf Insulation can support customers under Green Building Rating System certification:

  • LEED


  • HQE

  • WELL

  • We have a range of annually updated SUPAFIL factsheets 

  • We can provide you with expert advice 

Available from the Knauf Insulation website:

  • Environmental Product Declarations

  • Green Building Rating System factsheets

  • Annual Reports and Sustainability Guides

  • Certification

REASON 9 - We have nothing to hide

SUPAFIL is 99% Glass Mineral Wool and less than 1% additives

  • Knauf Insulation is committed to third party independent disclosure to demonstrate that SUPAFIL contains no hazardous substances.

  • SUPAFIL is Declare Red List free and supports LEED, WELL and LBC certification.

  • Knauf Insulation was the first Glass Mineral Wool insulation brand to be listed in the independent International Living Future Institute (ILFI) Declare List for US products.

  • The 1% of additives are composed of silicone to guarantee water-repellence, mineral oil to avoid dust and improve  insulation flow and an anti-static to reduce electrostatic charge.

SUPAFIL has achieved the highest Declare level and is free of harmful Red List ingredients:

  • Red List contains the worst-in-class materials prevalent in the building industry.

  • SUPAFIL contains no added formaldehyde, no flame retardants such as boric acid and ammonium sulphate and no mould preventing substances.

  • The commonly-used chemicals on the Red List are environmental pollutants that bio-accumulate up the food chain until they reach toxic concentrations and are harmful to the health of construction and factory workers.

REASON 10 - We are leaders in sustainability

Buildings generate nearly 40% of annual global GHG emissions. 

Construction business has a very significant impact on climate change and immediate actions have to be taken.

At Knauf Insulation, we have developed our sustainability strategy with strong commitments. Read more about our For A Better World Startegy.

Global Emissions Chart-resized

We are proud of our sustainability achievements
Knauf Insulation is committed to acting as a responsible company and is a front-runner in terms of sustainability 
Knauf Insulation is recognised for its Green Buildings expertise. 

Sustainability is a cornerstone of our business
Our experts can support customers under Green Building certification (LEED, BREEAM, HQE and WELL among others) and annually updated SUPAFIL® factsheets are available for download.

Our annual review showcases our sustainability initiatives
These initiatives help us make significant progress in achieving the ambitious sustainability targets we have set ourselves for 2025. The review also demonstrates how we put sustainability at the heart of everything we do.

For A better world brochure cover