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

Hello! In another thread I was advised to introduce my project here. First of all, we are still at the very beginning of the planning, got a plot of land with a lot of luck and now have to read up on everything. Tips, criticism, suggestions, etc. are always welcome.

Here are "our" key data:

- We are 2 adults, no children, none planned for now
- Electricity consumption: approx. 3,000 - 3,500 kWh
- Hot water consumption: I don’t have it handy right now, but rather high since we shower warm every day
- Reasonably handy, so we would like to at least paint (inside + outside) ourselves, lay floor coverings (except tiles), and do the garden completely ourselves (already have experience in all these areas)

Here are the key data of the plot:

- Plot 480 m²
- New development area
- 2 parking spaces required
- 2 full floors mandatory according to development plan
- Ridge direction East-West, regenerative energies desired according to development plan, photovoltaic possible as independent roof covering

And here is what we want as a house:

- Ground floor with living room, kitchen, guest room, and bathroom with shower
- Upper floor with bedroom, dressing room, bathroom with shower, office 1, office 2
- Basement with technology, utility room, possibly sauna and fitness, but it could also turn into just fitness + sauna in the garden
- Central long straight staircase as a "design element"
- approx. 80 m² living space per floor
- Garage, desired is a garage attached to the house (prefab?) with direct access to the house + carport on the other side of the house (unfortunately prescribed by the development plan)

According to the current planning, we want to (here I am still very uncertain, so criticism always welcome):

- build to KFW55 standard, even though there is no funding, or build approximately to that --> KFW40 does not seem worthwhile from my perspective?
- natural gas connection is laid directly to the plot, so currently my favorite is natural gas heating in combination with solar thermal (for hot water and heating)
- photovoltaic is rather not planned, I don’t see the advantage currently with the low compensation
- a ventilation system, although I don’t yet know whether central or decentralized

I can’t think of anything else at the moment – comments on anything always welcome.

Thanks and kind regards!
Elias

Two full floors strictly necessary according to the development plan

Really mandatory two?

Garage, the wish is for an attached (prefab?) garage with direct access to the house + carport on the other side of the house (unfortunately specified by the development plan)

Does the development plan specify an interior door?

- central long straight staircase as a "design element" - approx. 80m² living space per floor

That is a contradiction. Hopefully symmetry doesn't come with that too.

build according to KFW55 standard, even if there is no subsidy, or roughly so --> KFW40 is not worthwhile in my view?

I share this view, and the fact that the standard is no longer financially supported obviously makes you a bit freer to fulfill it a little less precisely/incompletely.

Welcome!

A couple of things immediately catch my attention. A straight staircase with 80m2 of living space on the ground floor will be difficult and will probably ruin the floor plan. Ours is over 4m long – it needs a lot of space and if it is desired as a design element, it needs even more space to have an effect.

I wouldn’t do Kfw 40 either. It is significantly more expensive and demanding, and if you don’t want photovoltaics, it doesn’t work anyway.

Why are you planning a ventilation system? I’m just curious. I’m old school and prefer to air out 2-3 times a day.

I saw your other thread and would plan the sauna in the garden. It is much nicer afterwards to simply go out into the fresh air. And you never really create a proper wellness area in the basement. It usually becomes a place where things are stored and it rarely becomes truly inviting and relaxing. Some friends have the sauna in the basement and it is rarely used. If you have space, I find a small sauna in a large wellness bathroom on the upper floor very nice. Best with a small balcony nearby to go outside.

I would only build passive houses from now on. If you subtract 30k for the heating and add the subsidies, you break even after a few years of operation. Otherwise, you pay a lot of money every year just for a warm place and then have to install a new heating system every 20 years. That will annoy the heirs even more.

If that doesn’t work, you definitely do NOT install gas anymore. Currently, gas is being phased out so that you can switch to a heat pump. This is even subsidized. In more and more countries, gas is already banned or will be soon. Not to mention that you can’t sign a new gas contract anyway at the moment...

Photovoltaics should ideally cover the entire roof – underneath, corrugated sheets are enough. You won’t see it anyway. You probably won’t be able to choose that by the time construction starts. Tip: A photovoltaic system is the only component of the house that generates income. Planning and installing it directly during construction is the cheapest option. It always gets more expensive later. The current feed-in tariff pays off the system 100%. By the time you build, either direct marketing at higher prices or an increased feed-in tariff will apply. There’s still some time.

It may all sound extreme at first – but if you spend a few evenings dealing with the topics, it’s not so bad. ;-)

How is the plot? Slope?
In which region are you building? BY?
Expensive area?
Considering what you have planned, how high is your budget?
How do you want to approach the topic?
Ideas?
Architect, prefab house company, BU? Etc.?

There are different opinions about the energy standard, if it's not your top priority don't dismiss it right away, depending on the house and construction method sometimes the step isn't too big.

Gas and solar thermal energy wouldn't be my choice nowadays with the developments.

Why are you planning a ventilation system? Just curious. I'm old school and prefer to air out 2-3 times a day.

Why shouldn't you do it? The main reason is comfort. You simply don't want to go through the house three times a day and open everything up. But there are plenty of other reasons as well.

Why shouldn't one do that? The main reason is comfort. You just don't want to go through the house three times a day and open everything up. But there are plenty of other reasons.

Actually, it is to have fresh air in the house! But I understand that many don't feel like doing that.