Ceiling insulation

Hi everyone, new here. I have just purchased my first home and need to put in some ceiling insulation batts. Does anyone have any suggestions on what R-value is the best for WA heat and where to find it at a low price? Thank you!

How is the rest of the house insulated? R3 if it’s not, R4 if it is. Insulation suffers from diminishing returns on $ per sq/m.

The rest of the house is double brick, so no insulation in the walls. If it’s not insulated anywhere else shouldn’t I aim to get a higher Rvalue for the ceiling?

You can do a retrofit wall insulation for your double brick InsulGuard Cavity Shield | Cavity Wall Insulation for New & Existing Homes (insulguardinsulation.com.au)
Just waiting on a quote for our house now.

Imagine you’re sleeping on a mattress in winter. You are cold but only have a $1 tea towel to cover you. Still cold. You have another tea towel but it cost $10. You add that but you still have cold feet. Next one costs $100 and again your feet are still cold.

Covering only 1part of your body is like insulating only 1 part of the house. Heat/cold is gained/lost through walls floor and windows.

For Perth, the government's 'Your Home' website recommends a minimum of R4.1 for the roof/ceiling, R2.8 for the walls

https://www.yourhome.gov.au/passive-design/insulation