Finance & career: Continuous financing for home loan

Hello everyone,

We bought a house a few years ago and, in addition to a larger loan, we took out €100,000 from KFW Bank, with a 10-year term. After the 10 years we need follow-up funding, the remaining amount is €70,000.

Let’s assume we still have €30,000 in savings at that point and are looking for follow-on funding for €40,000. Does the small amount even help a bank?

I would like to have low monthly borrowing costs over a long period of time, for example €100 per month for 20 years. Is that true?

Or shouldn’t you invest your savings and find something for €70,000?

Thanks for your suggestions