Considering refinancing your mortgage for a lower interest rate can save you money over time depending on charges, and the amount left outstanding on your mortgage. If you hold a variable rate mortgage you can expect to pay a penalty of three months interest, and if you hold a fixed rate mortgage, you will pay the greater of three months interest or interest rate differential penalty (IRD). Based on these costs, it might take you a bit of time to breakeven and start saving, however it is a great way to potentially save on your overall mortgage interest costs.