Financing Single-family house 520TE current market situation / year-end business banks?

So, this is how I see it with the costs:
Loan with savings building society contract

The years 2024 – 2043
Monthly installment interest for loan: 1398.25 ==> Total interest 335,580.00
Monthly installment savings building society contract: 628.00 Together: 2026.25
=628*20*12=150,720 paid in Loan from this should be 326,000 = together 476,720 ==> Costs 6,720.00

The years 2044-2057
Monthly installment building society loan: 2,330.00 ==> Total interest: 45,500.18

Option 1 - Costs: 335,580.00+45,500.18+6,720=387,800
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Loan 420,000 and KFW loan ... slightly modified, you didn’t say how much you want to keep in ETFs to repay the residual debt KfW, so here the total rate at the beginning is as high as in the building society contract variant, so the KfW residual debt is only 18,672
The first 10 years:
Monthly installment loan = 1,669.50
Monthly installment KfW = 357.00 ==> Together: 2026.50 ==> Residual debt: 18,672.78

Then also modified here and the previous KfW rate taken into account as a partial saving for annual special repayments
Afterwards 2034 - 2048:
Monthly installment loan = 1,669.50
Monthly portion special repayment = 350.00 (4,200/year) ==> Together: 2019.50

This then leads to the fact that the special payments can be stopped in the last 8 years and one is finished after 33 years, just like with the building society contract
Afterwards 2049 – 2057:
Monthly installment loan = 1,669.50

Option 2 - Costs: 305,061.00 (loan interest)+11,512.78 (KfW interest) = 316,573.78
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And then there is the option to set the KfW rate high enough so that after 10 years there is no residual debt. That would mean approx. 120 euros more rate in the first 10 years than in the building society contract variant, but no ETF or similar needs to be saved for the residual debt anymore

The first 10 years:
Monthly installment loan = 1,669.50
Monthly installment KfW = 485.83 ==> Together: 2155.33

Then again with partial annual special repayment
Afterwards 2034 - 2048:
Monthly installment loan = 1,669.50
Monthly portion special repayment = 350.00 (4,200/year) ==> Together: 2019.50

Afterwards 2049 – 2057:
Monthly installment loan = 1,669.50

Option 3 - Costs: 305,061.00+8,724.00 = 313,785.00

CONCLUSION
All 3 options are completed after 33 years, option 3 saves around 76,000 euros compared to option 1.
If in options 2 and 3 the special repayment is maintained in the last phase, one is even finished earlier and has paid even less interest.

So, this is how I see the costs:
Loan with savings building loan contract

The years 2024 – 2043
Monthly installment interest for loan: 1398.25 ==> total interest 335,580.00
Monthly installment saving building loan contract: 628.00 Together: 2026.25
=628*20*12=150,720 paid in Loan from this should be 326,000 = total 476,720 ==> costs 6,720.00

The years 2044-2057
Monthly installment building loan: 2,330.00 ==> total interest: 45,500.18

Variant 1 - costs: 335,580.00+45,500.18+6,720=387,800
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Loan 420,000 and KFW loan ... slightly modified, you did not write how much you want to invest in ETFs to pay off the residual KfW debt, so here the total installment at the beginning is as high as in the building loan contract variant, thus residual KfW debt only 18,672
The first 10 years:
Monthly installment Loan = 1669.50
Monthly installment KfW = 357.00 ==> Together: 2026.50 ==> residual debt: 18,672.78

Then slightly modified here as well and the previous KfW rate counted as a proportional saving for annual prepayment
Afterwards 2034 - 2048:
Monthly installment Loan = 1669.50
Monthly share prepayment = 350.00 (4200/year) ==> Together: 2019.50

This leads to the fact that you can keep the prepayments for the remaining 8 years and then finish after 33 years just like with the building loan contract
Afterwards 2049 – 2057:
Monthly installment Loan = 1669.50

Variant 2 - costs: 305,061.00 (loan interest)+11,512.78 (KfW interest) = 316,573.78
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And then there would be the variant to set the KfW rate so high right from the start that there is no residual debt after 10 years. That would mean about 120 euros more installment in the first 10 years than in the building loan contract variant, but then no ETF or such would have to be saved up anymore for residual debt

The first 10 years:
Monthly installment Loan = 1669.50
Monthly installment KfW = 485.83 ==> Together: 2155.33

Then again with proportional annual prepayment
Afterwards 2034 - 2048:
Monthly installment Loan = 1669.50
Monthly share prepayment = 350.00 (4200/year) ==> Together: 2019.50

Afterwards 2049 – 2057:
Monthly installment Loan = 1669.50

Variant 3 - costs: 305,061.00+8,724.00 = 313,785.00

CONCLUSION
All 3 variants are completed after 33 years, variant 3 saves about 76,000 euros compared to variant 1.
If you keep the prepayment in the last section in variants 2 and 3, you actually finish even earlier and pay even less interest.

Great praise!
Heartfelt thanks

... what calculations did you do to come to the statement "costs almost identical"?

... what did you calculate to come to the statement "costs almost identical"?

I only looked at the costs of the building savings contract on the screen with the bank advisor. The exact costs (effective interest rate) are/were not provided for the building savings contract. Therefore, he roughly calculated it for me ... I also received an offer from the bank. That should be the "cheapest" option. Would you take the risk of a 16-year fixed interest period? It would look like this: Annuity loan EUR 470,000 with a term of 40 years, fixed interest period 16 years, nominal interest rate 3.40%, installment EUR 1,780, special repayment option 5% per year

Are you calculating the costs? Why now such an offer with the lower monthly rate? At the beginning, you only have 1.14% repayment. There are financing calculators on Baufi24 where you can simply enter the values.

Last offer from you:
Annuity loan EUR 470,000 with a term of 40 years, fixed interest period 16 years, nominal interest rate 3.40%, rate EUR 1,780,--, special repayment option 5% per year
==> EUR 397,456.00 interest payments, if the interest remains the same after 16 years, interest rate risk after 16 years


If you at least design the conditions so that you pay the previously planned rate of EUR 2,019.00 per month, it changes as follows:
==> EUR 298,923.00 interest payments, if the interest remains the same after 16 years, still interest rate risk after 16 years (the calculator only allows 15)


If you take from your previous offers the annuity loan of EUR 470,000 with a 30-year fixed interest period and payment of EUR 2,019 / month
==> EUR 337,825.00 interest payments, interest rate risk only after 30 years


So why this lower rate now?

So, this is how I see the costs:
Loan with building savings contract accumulation

The years 2024 – 2043
Monthly rate interest on loan: 1398.25 ==> Total interest 335,580.00
Monthly rate saving building savings contract: 628.00 Together: 2026.25
= 628 * 20 * 12 = 150,720 paid in, loan from this should be 326,000 = total 476,720 ==> Costs 6,720.00

The years 2044-2057
Monthly rate building savings loan: 2,330.00 ==> Total interest: 45,500.18

Variant 1 - Costs: 335,580.00 + 45,500.18 + 6,720 = 387,800
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Loan 420,000 and KFW loan... slightly modified, since you did not write how much you want to store in ETFs to pay off the residual KfW debt, here the total rate at the beginning is roughly as high as in the building savings contract variant, thus residual debt KfW only 18,672
The first 10 years:
Monthly rate loan = 1,669.50
Monthly rate KfW = 357.00 ==> Together: 2,026.50 ==> Residual debt: 18,672.78

Then also modified here and the previous KfW rate is considered as a proportional saving for annual special repayment
Afterwards 2034 - 2048:
Monthly rate loan = 1,669.50
Monthly portion special repayment = 350.00 (4,200/year) ==> Together: 2,019.50

This leads to the fact that for the remaining 8 years the special payments can be left out and then one finishes just as after 33 years as with the building savings contract
Afterwards 2049 – 2057:
Monthly rate loan = 1,669.50

Variant 2 - Costs: 305,061.00 (loan interest) + 11,512.78 (KfW interest) = 316,573.78
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And then there would be the variant to set the KfW rate immediately so high that after 10 years there is no residual debt anymore. That would mean about 120 euros more rate in the first 10 years than in the building savings contract variant, but for that no ETF or similar has to be saved for the residual debt anymore

The first 10 years:
Monthly rate loan = 1,669.50
Monthly rate KfW = 485.83 ==> Together: 2,155.33

Then again with proportional annual special repayment
Afterwards 2034 - 2048:
Monthly rate loan = 1,669.50
Monthly portion special repayment = 350.00 (4,200/year) ==> Together: 2,019.50

Afterwards 2049 – 2057:
Monthly rate loan = 1,669.50

Variant 3 - Costs: 305,061.00 + 8,724.00 = 313,785.00

CONCLUSION
All 3 variants are completed after 33 years, variant 3 saves about 76,000 euros compared to variant 1.
If you keep the special repayment in the last section in variants 2 and 3, you will even be finished earlier and have paid even less interest.

Sorry that I am only getting back now!
I have taken a look at the total costs of the two "favorites," i.e. annuity loan vs. building saver.
For that, I created the following calculation, is the perspective on total costs comparable like this?

Annuity model Bank 1:
TEU 420: 470 months x 1,629.96 = 787,955.00
TEU 50: 12 months x 135.83 = 1,629.96
288 months x 250.52 = 72,149.76
Total 861,734.72

Building savings contract model building savings bank and Bank 2:
Accumulation phase
TEU 470: 240 months x 2,018.42 = 484,420.80
./. 1 monthly saving rate building savings contract 628,-- = ./. 628.00

Building savings loan phase
161 months x 2,328.74 = 374,872.40
Total 858,665.20 (plus building savings contract closing fee)