Mortgage- port or new lender?

[Combusting]

Planning ahead for our big house move due October 2025…. Which will be upsize/up-area moving closer to DC schools than we live now.

In Oct 2025, we will still have our current mortgage fix on a low rate (2%) up till Oct 2027. In my mind it makes sense to apply to current lender to port it with the additional borrowing (hugely higher salaries now, and in 2025, 30% deposit etc) because -

1. It helps keep roughly half of our total new borrowing to our current low 2% rate till October 2027 as the ported mortgage continues at it's 5 year fix rate as planned with any new additionall borrowing at a higher rate (assuming rates settle at 4-5%).
2. And helps avoid paying the ERC which we would otherwise have to pay if we left current lender.

Obviously a whole market broker can help better crunch numbers but my main thinking is that a brand new mortgage places the entire borrowing for new house at 4-5%. And we pay ERX. But a porter mortgage keeps about half of our borrowing at the current fix of 2%, meaning only half of the mortgage we take out as new borrowing sits at the higher rate. And avoid ERC.

Is that right?

Bumping just in case someone sees this!

It all comes down to your individual lender - will they allow you to port, will they happily lend you the extra money, etc?

This might help answer the main questions you have but it will all come down to the individual terms you have.

https://www.moneysavingexpert.com/mortgages/porting-your-mortgage/

There are a number of factors that I would look at if it were me:
Does your current product allow you to port the mortgage?
How much are your ERCs?
Will your current lender lend you the additional money?
At what rate will they lend you the money?
What percentage of your borrowing will be on the lower rate?
At what rate can borrow if you moved to a new lender?
If you get a better rate with another lender does this cover the ERCs and the lower existing rate?
Basically it’s crunching all the numbers and working out which is cheaper.

Thanks. Yes porting is allowed otherwise we wouldn’t be considering that option :)

If we stayed with current lender - 50% of the total new mortgage would be on 2% till the end of 2027, and 50% would be on whatever new rate we are given.

in my mind this would be better for us than 100% Of the total new mortgage being on whatever new rate we are given.

obviously we need to see what this hypothetical new rate will be in 2 years time but I’m struggling to see that it will be 2% for any length of time ….

And whether they’d be willing to lend more - the size of our deposit, both our salaries etc all point to the same affordability figures across current and several other lenders.

so affordability isn’t what I’m asking about. Assuming 1) affordability and 2) porting allowed - in these circs purely thinking about what a better financial option might be given that staying with current lender will ringfence half the mortgage at a low rate for a couple years.

but yes if we find an incomparably low rate with a long ish fix with someone else that might make more sense!!

It sounds like you're likely to be better off porting but won't be able to tell until nearer the time. The main drawback I have heard from porting is that you can end up with fixes ending at different times which can make subsequent remortgaging more tricky for timing and potentially paying svr on the first rate to expire