Does an offset account earn interest?
No, offset accounts do not earn interest. Both your Spend and Save accounts can offset your variable rate Own home loan.
If you make your Save account an offset account, you will only receive the base interest earned in that month up until the change was made. No bonus interest will be paid. You can choose to wait till the first day of the next month to make your Save account an offset account if you want to earn any payable bonus interest for the previous month.