Hi,
Take a look at the tables in 1st post here:
https://www.askaboutmoney.com/threa...e-the-lowest-mortgage-rates-available.205864/
AIB is lowest variable rate at 2.75%
However, UB and KBC have fixed rates lower than this.
Say if you went with UK 2 year fixed @2.3%, and at the end of 2 years they match whatever rate AIB have at the time, you'll have saved 1300 in interest.
It's impossible to know what the market will be like in 2 years, and which lender will be cheaper, so personally I would go with the lowest rate available right now.
Or... if you wanted certainity for the entire of your mortgage go for a 7 year fixed rate. UB would be 2.99% for that term. Although the rate is fixed, you can pay off an extra 10% of the balance each year without incurring a break fee.
(I could be completely wrong, but I've assumed based on memory of some of you previous posts that you are not too far off retirement which is why I'm suggesting the fixed rate, which can help with financial planning).
If you want help calculating any particular scenarios, post them up and someone will help you.