Firstly, both current account and offset mortgages are based on the same principle - money is saved and offset against your mortgage debt, which in turn lowers the rate. So if you have either current account and offset mortgages the more you save each month, the lower the rate of interest. But there are differences.
The first form of offset is current account offset. This mortgage changes it's rate with the more money you invest into it - both current account and offset mortgages do this. But current account offset works as a giant overdraft - once you take out the mortgage you are in negative figures with the lender. Then as money goes into the account, the overdraft shrinks
and the rate drops. People choose this form of offset because it is a great way to consolidate other debts - including any unsecured or credit card debt onto the current account means you will be paying a much lower rate on the debt - the average offset rate is far lower than any credit card rate of interest. So although both current account and offset mortgages allow for debt consolidation, current account offset makes it easy.
Offset mortgages differ from current account mortgages inasmuch as the mortgage is tied to current accounts, rather than based on one. Current account and offset mortgages both need accounts to work, but current account is just a single bank account where all of your debts and savings can be thrown in together. Offset instead links to both banking and saving accounts and works directly with their balances. So if you invest into your savings account, your rate will drop, but if you spend from your banking account the rate will rise. This mortgage is good for those borrowers who have a lump sum in a savings account, but also have a current account, or several current accounts, that are filled on a regular basis.
So which one is best? Current account and offset mortgages both encourage saving and both current account and offset mortgages will help you in the long run. It's a tough call and a decision as big as a mortgage should not be taken lightly. Talk to a mortgage adviser and let them give you a fair and unbiased decision - offset always needs professional advice, however much you have to spend.
