I will use this case as an example about how to approach the problem.
Rule 1 - look at the interest saved. Do not look at repayments as they involve capital repayments as well. An option with higher capital repayments might look more expensive but higher capital repayments means you will owe less at the end.
Rule 2 - Calculate the savings for the remaining term of the existing fixed rate and not for the full term of the new fixed rate.
Using Cutha's figures
Mortgage balance: €263,000
Remaining term of existing fixed rate: 23 months
Difference in interest rates: .75% (2.9% existing rate - 2.15% new rate)
Interest saved = mortgage balance x difference in interest rates x remaining term on existing fixed rate
Interest saved = €263,000 x .75% x 23/12 ( 23 months over 12 months)
Interest saved = €3,780
Break fee: €3,580
So assuming interest rates remain the same over the next few years, it does not look like it's worth paying €3,580 up front to save €3,780
Rule 3 - If you decide not to switch, keep the decision under review
The factors may change quickly which would make a switch worthwhile.
- The rates available from another lender may fall
- The break fee will fall as the remaining term reduces
- The break fee could fall if money market rates change