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Glasswool vs Rockwool vs Polyester vs Rigid board insulation

Reflective foil is not an insulator in its own right, but relies on a minimum 25mm clear air space beside the foil to be effective. It is more effective to keep heat out than in a building. 

Insulation batts and blanket

Batts and blanket are the reliable and price competitive option for insulation when these are kept dry. Wet batts or blanket lose a significant amount of their insulation benefit.

Glasswool insulation is fibreglass based insulation. Many glasswool manufacturers use the dangerous formaldehyde as the binder in the product. Dangerous chemicals: Select products that do not use formaldehyde as a binder. Recycled content: create a market for recycled glass product by specifying a product that has greater than 50% recycled content. Re-use: Clean glasswool batts are re-usable. Recyclability: currently glasswool batts are not recyclable in Australia. Specify:  Earthwool, CSR Bradford Gold batts (Green Tag certified ) or equivalent.

Polyester insulation is more expensive but does not cause itchiness during installation. Recycled content: Polyester insulation is typically contains a high recycled PET plastic drink bottle content. Re-use and Recyclability: Polyester insulation is readily re-usable and if clean is recyclable. Confirm where this will occur. 

Wool and polyester blend insulation is also available from Golden Fleece. More information required about this product. 

Cellulose insulation is perhaps the most sustainable insulation available. Cellulose is an organic compound that constitutes the primary cell  wall of green plants and is the most abundant polymer on Earth. Cellulose insulation has good thermal insulation properties (heat conductivity = 0.04 W/(m·K)). It also acts as sound insulation.

Cellulose insulation is made from recycled newspaper (75-85%) and from natural fire retardants and anti-fungal agents such as boric acid (15-25%). Newspapers are shredded and mixed with boric acid before being turned into small fibres. These are packaged for installation on site. Cellulose insulation is mostly used in roofs and walls and is typically blown. Embodied Energy: It has a significantly lower embodied energy than glasswool. See the Uni Melb EPiC. Specify: Insulfluff

ThermoJute 100 - insulation product made from single use jute bags (from the plant Corchorus). See

Underslab soffit insulation - Knauf Earthwool Building slab is a range of rigid and semi-rigid, resilient, noncombustible rock mineral wool boards for use insulating car park soffits. 

Expanded Polystyrene (EPS) is the common polystyrene used in upper level cladding and has a similar performer to insulation batts in terms of insulating quality for thickness. EPS is a recyclable product at many council waste depots, however there is the danger in using and cutting polystyrene board on site that not all particles will make it into the bin and will blow off-site causing damage to bird and animal life outside of and also in waterways.  

Clinka fill under-slab insulation ClinkaFILL is just the loose ‘Clinka’ balls and is suitable for insulation under slabs, where a 150 mm layer of clinkaFILL provides around R1.77 of insulative value and eliminates the need for a vapour barrier. It can also be used for backfill against retaining walls to reduce hydraulic loading, as a green roof drainage material and as aggregate in concrete to reduce weight. (From Renew Issue 142).

Insulation: About
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