Glasswool Batts are currently the cheapest insulation alternative on the market.  
Fletcher Insulation manufactures in Australia 

                                                                                          

Pink Batts® from Fletcher Insulation™ have been trusted by Australians since 1956. Pink Batts® insulation reduces heat transfer by up to 60% resulting in great savings on your energy bills, not to mention how comfortable you’ll be.
In fact Pink Batts® insulation can reduce summer heat in your home by up to 12°C.

Also available, is a high density underfloor insulation system that is easy to install in new build, renovation and retrofit applications. This versatile high density insulation solution provides outstanding thermal performance, reduces heat transfer between suspended floors and reduces heating energy usage.

Pink Batts deliver excellent acoustic performance for domestic applications. Ideal for insulation in metal and timber stud wall systems, and as infill between floors and ceilings.

The premium cavity infill batt for room-to-room noise control. Installed in ceilings, between floor and internal stud walls. These products minimise airborne sound transmission using standard construction methods and timber sizes. Perfect for rooms where extra noise protection is required, such as bathrooms and movie rooms. 

High density glasswool insulation batts with excellent acoustic properties suited to residential wall applications may also be used to achieve a high R-value in a small wall cavity.

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