EH 790K€, financing 480K€ - feasible with our monthly budget?

I was too late.
At 1%, with your rate, you would have paid 33,000 EUR in interest to the bank after 10 years. Even if the interest rate then increased to 4%... the 130,000 EUR is "in the bag"...

Fortunately, we also have a actually quite good net income. Since we pay everything by card, I have had a very good overview of our expenses for years and was able to create a very precise household budget. In the end, at the current expenses, we could pay a rate of 2300 EUR. Anything above that would mean that we would have to cut back somehow and there would be no buffer left. And assuming that the house would not cause more additional costs than our current apartment, which is probably very unrealistic. Large plot purchased cheaply approx. 100T EUR, paid with equity. Another 100T EUR equity for the house plus 450T EUR loan. At current interest rates of about 4%, that already puts us at a rate of 2250 EUR. And a house for 550T EUR with about 150 sqm for a family of four means that everything must be finished at about 3600 EUR / sqm. From everything I have read, that is already tight and then I definitely have the smallest house in the neighborhood. I don’t know where I’m calculating wrong, but I thought I had quite comfortable conditions. I would not see it that way anymore now.

You can still manage with a 2300 rate, even if it’s tight at 4%. But: As you described, that would be your maximum possible burden and you would end up at zero at the end of the month or would have to cut back? I wouldn’t do that. Keep in mind that a new house is not new forever either, washing machines break down, cars require maintenance and so on. Building reserves for household and for house maintenance (which means that after 15 years, bigger repairs or a new heating system will also be due) is, in my view, not optional. The house will probably also cause higher additional costs, although this can vary greatly depending on the case. If you currently live in a poorly insulated old building, you can save some energy, but the area will be larger with the house, so it often doesn’t work out. In addition, there are things like garbage fees, property tax, other charges – you’ll be surprised what all comes in. I had never heard of the Leda-Jümme association and still don’t know exactly what they do, but as it turned out, I owed them money back then simply because I owned a plot. :D

Where I see room for maneuver for you is the costs. Being the smallest house in the settlement is no reason to be ashamed. Owning a house already puts you in the top 10% today. And I think, depending on the region in Germany, you can also come out below 3600€ in costs.

Even if the rate is tight at the beginning, one should keep in mind that from 8,000 net, due to inflation-related wage increases, it will become at least 9,000 euros within 5 years and at least 10,000 euros after 10 years. In this respect, a rate that is borderline at the beginning becomes significantly less critical over time because the rate remains constant.

Hmm, so generally that is not correct. A special repayment of 5% was included with both of our financings so far without discussion or interest surcharge.

Really? At which bank were you? I thought special repayments always cost extra. We sometimes had an interest surcharge of up to 0.25%.

Really? Which bank were you with? I thought prepayments always get expensive. We had interest rate surcharges of up to 0.25%

The first time, we received offers through Interhyp, including ING and a regional bank in the northwest. I believe both included 5% per year. We ultimately signed with Sparda West (we had contacted them ourselves), which had the cheapest interest rate in comparison and also offered 5% per year as prepayment. However, we did not ask if it could be cheaper without that option. For me, that was also set as "important." This time, we are with ING via Interhyp, and the 5% was included right in the first offer. But now I'm uncertain; maybe we told the Interhyp advisor that this was important to us. Maybe someone from the forum knows if ING also offers an "interest rate discount" when you forgo this? Their offers available online almost always include these 5% as well.

The first time we received offers via Interhyp, among them were the ING and a regional bank in the northwest. Both, I believe, included 5% per year. We ultimately signed with Sparda West (we had contacted them ourselves), and they had the best interest rate in comparison, also offering 5% per year as special repayment. However, we did not ask if it could be cheaper without this option. For me, it was also set as "important."

This time we are with ING via Interhyp, and the 5% was also included directly in the first offer.
Now I’m uncertain; maybe we told the advisor at Interhyp that this was important to us. Maybe someone on the forum knows if ING also offers an "interest discount" if you forgo this? Their offers that can be found online almost always include these 5%.

For us, it was also directly included with the local VR Bank. I asked the advisor whether annual special repayments were already included, and the answer was that it is those 5% annually, and if you want more, it would make the interest rate more expensive.
Whether the interest rate would have gone down if we had completely waived it, I don’t know either, as I didn’t ask.