To Insulate or not and cost of doing so

[Dan_574]

if you are doing it yourself definately get polyester batts or similar not glass wool they are a bit cheaper but they are EVIL. 2 years ago I did my house I used r3 polyester from insulation wholesalers in braeside 95873154 cheapest I could find at the time. we had moved in before we put them in and boy was it cold once the batts were in great.
I did read that the only heat you loose through unisulated timber floors is radiant heat so if the only form of heating you have is convection then the benefits are minimal, the real saver is when you can block out all the draft, heavy drapes, pelmets etc.

[Carpenter]

I do not know for certain, but I think Aircell insulation would also be a good option for under floors. http://www1.aircell.com.au/. Tha benefits I see is that you can easily cut strips to suit the gap between joists, then simply staple it up there with the pneumatic stapler. There would be no gaps or space for vermin to set up home in, & I think you would get at least R2 performance.