KfW-Effizienzhaus 40 Plus construction costs and KfW funding possibilities

Hello dear construction experts and builders with experience

I am a young 25-year-old engineer with plans to start a family and related building/purchasing ideas.

For about a month now, I have been thinking about how to start life with the goal of eventually owning a house.

One could say that I have zero professional knowledge regarding house construction and financing.
For me, there are two possibilities:
-I build myself a house after finding a plot of land - We are about 5-10 people with over 10-30 years of building experience who are very skilled craftsmen and can put together a lot ourselves.
-I buy a finished house.

Like many young people who start life without noteworthy inheritance, I also think about finances, as I would describe myself as very cost-conscious.
Now I have already attended one house viewing as a trial to find out how such a viewing works and what to pay attention to and then had a bank consultation appointment about "How could I buy such a house."

My idea is to own a house with a 1st floor (3-4 rooms) + ground floor (4-5 rooms) + granny flat (2-3 rooms) + garage (2 cars) with some garden. I would like to rent out the 1st floor and the granny flat at the start and later, if needed, possibly use them myself.

I estimate the costs would depend on the local area/building year etc. and would be at a cost level of 500k€+.

My bank advisor advised me to save capital in the amount of 50-70k€ and then dare to start the house search/building project. He also advised me to create building savings contracts and possibly invest in funds to increase my capital. And then, at an interest rate of 1-1.5%, one could find something to finance the rest.

Now I happened to come across KfW loans on the internet and saw quite interesting figures and keywords. That one could already take out loans of 120k€ per apartment at interest rates from 0.50% and that there are repayment subsidies depending on efficiency, child construction allowance, etc.

Here it now specifically says that with a KfW Efficiency House 40 Plus you get a 25% repayment subsidy and up to max. 30k€ supported by the state. You are obliged to build accompanied by an energy expert and would also receive 50% up to max. 4k€ to cover his costs.

My question to you experts is: What would a house like that cost me approximately "1st floor (3-4 rooms) + ground floor (4-5 rooms) + granny flat (2-3 rooms) + garage (2 cars)" including all the energy-related MATERIAL stuff? Can anyone give me a rough thumb value? Or a rule of thumb?

I am talking here from the necessary to medium level. Would the whole thing cost me 300k€ or 500k€ or 750k€ or 1 million €? Because, as I said, I could have a maximum of 360k€ loan available here = 3*120k€ and it would be very interesting to know how much remaining sum I would have to finance otherwise.

I hope I was able to explain my concern as precisely and "short and crisp" as possible

Thank you very much I hope for help..

So you are envisioning a three-family house with around 300 sqm of living space that you want to build entirely by yourself and currently have no clue about anything, but only see a subsidy for an expensive energy standard. The necessary to medium standard is out of the question, since you have to invest a high technical effort per se.
As a construction company, you can simply calculate 330 sqm x €2,500. Plus ancillary construction costs + basement (your tenants will need some storage rooms or the building services must be installed for three apartments) + outdoor facilities + parking spaces (with three apartments it will rather be six parking spaces than just two in the garage). So the pure house without land will already be a seven-digit figure. And since you definitely won’t get by without labor costs (who among “us” has enough time, desire, and motivation to just build your multi-family house for a year or longer), the fun will be relatively expensive in the end. Maybe you save €50k labor costs, or €100k, or €200k? Just ask “us,” who have construction experience.
You should have good creditworthiness = net income from €4k as well as equity of €200k+X.

Overall, you’ll be better and cheaper off with a normal single-family house. Oh yes, who pays back the great subsidized loans after the 10-year fixed interest period when the interest rate is then at 3.5% or 5%? What if the house suddenly doesn’t fit the family planning or the new job in another federal state? Who pays for the conversion of the ground floor and upper floor into one residential unit and what does the bank say if suddenly one rent is missing? And if you like being in the garden and want to drink a beer with your buddies, you will have two other parties making a fuss because you are too loud. Etc.

Nice, but still totally naive approach.

What loan do you get from your bank anyway? By the way, the normal bank loan is not much more expensive (even if the repayment subsidy is missing).

P.S. If you get an existing property with your desired room layout for the price you mentioned, you either live in the middle of blooming landscapes or are buying renovation needs.

P.S. If you get an existing property with your desired room layout for the price you mentioned, you either live in the middle of nowhere or you are buying in need of renovation.

Thank you for the detailed answer. It is always interesting to hear opinions from different perspectives and also the opposite of my ideas. My preference is to build mainly in the countryside, as I generally like rural areas more despite the tempting infrastructure in urban areas. Does what you listed regarding costs and expenses also apply to prefabricated houses/architect houses? How could I find out what the total technical costs would be for an Efficiency House 40 plus? Regarding investing a lot of money in high technology and efficiency, I agree with you without much hesitation. Technology & efficiency can certainly cost money. But how can I get an idea of "how much?" In the end, I have to compare several options and make a decision. And I think the monetary aspect is the primary factor there.

Does what you listed regarding costs and expenses also apply to prefab houses/architect-designed houses?

Prefab houses are somewhat more expensive than solid houses. Architect-designed houses are both, since you won’t be able to buy a fully planned off-the-shelf house.

How could I find out what the total technology costs would be for an Efficiency House 40 plus?

Google and talk to house providers (for an indication). Alternatively, have a conversation with an architect. Otherwise, gather some information here in the forum – although most home builders shy away from the effort for a few € more efficiency, which you can hardly notice in daily life. You practically don’t notice whether you built 40 or 55. User behavior is much more decisive than a calculated value. In terms of renting out (and especially in rural areas), you won’t get any different rent for your investment anyway. So it’s unnecessary – probably the effort is higher than the benefit from the slightly higher subsidy.

And monetary aspects are probably the primary factor here.

Maybe you should rather say something about your financial background. If you are a young engineer without an inheritance, you practically have no creditworthiness. And your idea should then dissolve into thin air. Because planning now for in 5 years is pointless. At best, you can start saving equity. This may sound harsh but probably hits the point, right?

I would also like to point out that while a two-family house can often be built instead of a single-family house, it looks completely different with three residential units. So you first have to find a suitable plot of land, presumably in an area where you would also want to live permanently yourself.

You write about "sometime" and then again I get the impression that you want to get started right away. Then you glance at subsidies that are partly expiring ([baukindergeld]).

I assume that you want to build alone and a partner is supposed to move in later? What if she doesn't like your house that much and would rather reinvent it technically herself?

I would therefore advise focusing on the topic of "equity building" first and not immediately moving on to building.