How does an offset account work?
Here's an example: say you have $10,000 in your offset account and you currently owe $500,000 on your home loan. The money in your offset account ensures you only pay interest on your mortgage minus the money in your offset account. In other words, you will be charged interest on a $490,000 loan, rather than a $500,000 loan.
If you have a decent amount of money in your offset account from day one, you could find that it saves you thousands of dollars in interest over the life of your loan. But, keep in mind there may be higher monthly fees attached to the account and a minimum balance may be required in the account.