Should we finance our house 100%?

A. Full financing is rubbish B. Why do you have 0 equity? Spent it all so far? High rent? C. Who says your project will cost exactly €304,000? F. I would say something is fishy with the financing or some creative accounting has been done, as you won't be able to pay off €305,000 in 25 years with €1,400 monthly installments, even if you make small additional payments. Besides, does any serious bank still finance 100% nowadays?!?!?

Even with your scheduled special repayment (if you do it every year) you are only at a 2% repayment rate, which means in 10 years, when your fixed interest period ends (you probably wouldn't have gotten 4.44% with a higher rate), you will still have around 235,000 euros of debt, and then let the interest rates rise to 7%... So either scale back your plans or save up first for the big dream. Take a look with an interest/repayment calculator online to see what you can pay off in 25 years.