Planning of a single-family house (basement + ground floor + upper floor) on a 480m² plot

Are you planning now for 2 or for a family?

Why does the architect advise against a ventilation system? Sure, it costs money to purchase, but it provides a lot of comfort and your house doesn’t cool down in winter. Opening windows is always possible if you want. You have to manually exchange all the air and thus also the heat in the house at least 3 times a day.

Budget in Bavaria with a basement seems tight. Not impossible, but it’s not generous.

Consider whether you’d rather plan the sauna above ground.

We are planning for 2, why? Do you think it’s too much space? As described in the first post, there are two of us, we currently work and hopefully will continue to work mostly from home, so we need 2 offices.

The thing with the ventilation system sounds a bit like a matter of belief... she says it costs money, needs maintenance, can break, and you drill holes in the house for the individual elements, where energy can also escape. I think she’s not wrong. I have lived in rented apartments without a ventilation system since I was born and have managed well with ventilation. But I definitely have to read up on it again.

Oh, and read my post before that, the sauna has already moved to the upper floor ;)

However, some people here in the forum advised against it, and our architect also said yesterday that we should leave it be and rely on good old ventilation.

There are not that many here advising against it. My impression is that the opinion in the forum is clearly in favor of controlled residential ventilation. It’s not just about comfort, heating cost savings, and building protection. It’s also about CO2 levels in bedrooms and children's rooms. It’s about pollutant exposure from building materials and new furniture. It’s about dust and pollen entering through windows. A new building is almost airtight; there are no breathable walls. Don’t forget that and do some reading on the subject before trusting your architect, who probably just doesn’t feel like doing the extra planning.

I actually have to familiarize myself with the topic of passive building first.

If you already have an architect on board, that probably won’t happen: passive almost always means prefab house. But of course you can also insulate solidly enough to have very, very low heating costs. The better insulated, the more you can cover with (large) photovoltaics yourself.

She recommended geothermal energy yesterday,

For a new building that is not exactly located in the high mountains, it probably doesn’t pay off. New air-to-water heat pumps are hardly less efficient than ground-source heat pumps. But basically, there is nothing to object to. Oh, and it is often more space-saving as well.

I have to recalculate that.

Do that when you go to the final roof planning. At the moment everything is up in the air, and Habeck has to deliver first. Good luck going forward.

I had overlooked the sauna on the upper floor. No, I don’t think it’s too big. Without a floor plan it’s hard to discuss. Wellness and fitness are important to you. The sauna is now upstairs; I would also plan the fitness area upstairs. I find it more pleasant to look outside than at a wall. If there is a possibility, try to place the technology on the ground floor and fitness upstairs. Could save a few euros on the basement. Of course, it depends on how much of a slope there is. Talk to the architect about this. Modern houses are very airtight, even without a ventilation system. You can’t compare it to rental apartments, which are usually older. With a central ventilation system, you have two openings in the house. One for supply air, one for exhaust air. Maintenance is regular filter replacement – about as difficult as changing light bulbs. For major defects, yes, eventually a service technician is needed. Heat recovery is an energetic big plus, the luxury of permanent air exchange, no foggy windows after showering, no musty bedroom in the morning. We have one because our house is a passive house; I wouldn’t want to do without it anymore. Windows are still opened, though. Especially in spring, it just smells good. Just read up on it. You can find quite a bit about it here in the forum.

First of all, I think it’s good that you are dealing with this so constructively.

Before you start focusing too much on individual things and details...start from the beginning.

Plot:

Slight slope. Define that a bit. You wouldn’t be the first to imagine filling it up a bit and so on, no problem. (Slight) slope could again argue for a basement and with clever planning also a good way to bring light into the basement...a light well etc. costs a lot of money with retaining walls and so on. Also a bit of filling up. Our plot dimensions are very similar. Slightly smaller and the retaining/filling + wall don’t come for free.

Budget:

BY very high-priced. Oriented around 330€/sqm not in the super expensive areas but also different than somewhere in structurally weak rural regions in the northeast or something like that.

Your calculation with your demands will be a very tight fit!

Just a quick calculation.

Plot (including ancillary purchase costs) approx. 165k
House 160m2 x 2,500€ approx. 400k
Here in the forum people like to calculate with 2,500€/sqm. Normal standard, often plus floors + painting. No special extras. BY actually more rather.
Basement approx. 120k (especially if not just a utility basement)
Additional construction costs 50k (earthworks, connections, etc.)
Garage 20k
Carport 15k
Kitchen, furniture, lighting, etc. 30k
Outdoor facilities (slope???) 30k

Subtotal: 830k

That puts us already 30k over your budget. And partly I have calculated here with rather low values for Bavaria. You still have the question mark slope and no sauna yet, no fitness room yet, no gimmicks with electricity or sanitary, no electric blinds/smart home or anything else...Edit: Passive house and geothermal are also missing.

By the way also no ventilation. Which I would place significantly higher in my priorities than a sauna.
Yes, mainly comfort. But don’t compare your user behavior from a rental apartment (old building?) to your single-family house.
New houses are tight. Really tight. You run through three floors two or rather three times a day and open everything and later close everything again. Do you really do that every day? Or bedroom. In the new build with closed windows you feel like you woke up in a puma cage the next morning. Of course, you can sleep with tilted windows. Whether that is energetically sensible in winter...just read up on that. Sauna in the garden you can also do later. In the bathroom I see it with your budget anyway not.

So good that you start addressing this early here. My tip remains...start at the beginning. Budget and plot.

I had a sauna plus a bathroom in the basement of my old house, and it was really beautifully done there. You felt very comfortable and, of course, there was plenty of space, also for lounge chairs, fountains, and so on. There was a staircase leading to the garden.

In the new house, we had enough space in the bathroom upstairs and therefore installed the sauna upstairs. Lounge chairs still don’t fit in, but we have a small balcony off the bathroom and then just lie down on the bed or on the sofa in the guest room upstairs. The rooms are right next to each other. This decision saved us an extra bathroom in the basement and the elaborate design of a nice wellness area. A sauna without a bathroom is simply not an option! The garden has to be completely private if you’re running around in a bathrobe. And the shower shouldn’t be a whole floor away, so you don’t have to climb the stairs dripping with sweat.

We have the fitness area in the basement, and that’s great especially in summer. It’s always nice and cool there and you can train wonderfully. I just turn the light on and that’s it... Upstairs would be too warm for me in the summer.

The thing with the ventilation system seems a bit like a matter of belief to me... she says it costs money, needs maintenance, can break down, and you drill holes into the house for the individual components, where energy can also escape.

There are no holes where energy could escape. A clear advantage: always fresh air, without you bringing the cold into the house by ventilating.

I have always lived in rental apartments without a ventilation system since I was born and have managed well with ventilating.

New buildings are very tight and not comparable to older existing houses. With a slope, a basement is of course very suitable, also to use some nice space, e.g., with a wellness room. However, I understood that you are still very, very early in the process and have not yet put any idea on paper. If there is a plan, then please post it here :)