Semi-detached house, upscale fittings: Are the additional costs correct?

Hello,

we met with an architect yesterday who showed us a plot of land for a semi-detached house. The other half is already built.
The house has 140 sqm of living space, although a large part of this already includes the basement, as it is habitable (with window).

The house's equipment is supposed to be upscale (I will copy the Immobilienscout listing at the end here).

The architect will be the general contractor and work with local craftsmen.
Additional services such as more sockets, different bathroom fittings, etc., I have to address directly to his respective craftsmen and they will then tell me the costs.

But now first the main questions:

Only a gas heating system with radiators in the rooms is installed.
He said if I want underfloor heating, it will be operated with an air heat pump.
Additional costs for this system + underfloor heating are about €15,000.
That sounded reasonable to me, as I had no idea/had no prior experience. In this forum, some have already balked because they would have to pay €8,000 more.
What do you say about my price?
And he kept saying that this air heat pump would be a solar technology?? Because it extracts heat from the air.

Furthermore:
Additional costs of about €18,000 for earthworks, sewer works, and house connections.
Is that okay?
He said that includes the earth excavation and the connection installation from the street to the house (electricity, water, etc.)

Another extra:
We could have a heat recovery system installed for about €15,000, with an air filter and so on. For allergy sufferers, like in passive prefabricated houses.
He estimates that with this, the KfW rating would even drop from 70 (which is normal) to 55.
Is the additional cost + health aspect worth it?
I am allergic to pollen and so on and get severe eye itching/burning, itching in the palate, etc.

Those were my main questions for now.

Further:
I forgot to ask about costs for electric roller shutters. What would you say?
And how much does a garage cost approximately?

And is a bedroom including a dressing room with 15 sqm big enough? It seems a bit small to me.

And finally:
The plot is located on a slight slope. That means about half of the basement is underground, or in other words, from the terrace a few steps down to the garden.
On the left side, the other semi-detached house, on the right side a stream, and behind the garden, directly adjacent with no space in between, the forest slope rises.
Occasionally there is apparently some wildlife visiting. (according to the neighbor: mice, 2 rats, a marten’s nest somewhere nearby, fawn, wild boar)
How would you assess such a property? We are basically city kids.

That’s it from me for now. Thanks for your help.

Here is the exposé:

+++ COMMISSION-FREE +++ "BAUHAUS-STYLE" IDYLL BY THE STREAM - with basement

Purchase price:
€289,820.00

Rooms:
5.00
Living area approx.:
140.91 m²
Plot area approx.:
420.00 m²
[B]Main criteria[/B]
House type:
Semi-detached house
Usable area approx.:
16 m²
Number of floors:
3
Bedrooms:
4
Bathrooms:
1
Guest WC:
Basement:
TV / Internet / Telephone:
Electricity consumption: from 2,500 kWh*
[B]Costs[/B]
Purchase price:
€289,820.00
Brokerage fee for buyer:
No
[B]Building substance[/B]
Construction phase:
House in planning (projected)
Quality of fittings:
Upscale
Heating type:
Central heating
Energy certificate:
Not yet available
Property description
Idyllically situated by a stream, secluded at the edge of the forest, an attractive, projected single-family house including basement, turnkey and solidly built, will be constructed here. In this generously designed and modern energy-saving house, your personal requirements will be fulfilled. Together with the architect, you can specify changes to the layout and fittings for your "dream house" according to your individual wishes. - generous and brightly sunny is the open living/dining area - lots of glazing with a view to the garden and terrace - room layout changes possible - master bedroom with dressing room and two children's rooms - daylight wellness bathroom - spacious living/workroom on the garden floor

Fittings
"Masterful quality by locally based specialist craftsmen" - developed basement - energy-saving, breathable, natural brickwork with additional full thermal insulation for energy-conscious comfort - heating system with efficient gas condensing technology optionally with solar collectors and underfloor heating - family-friendly daylight wellness bathroom with bathtub and shower - ceramic sanitary objects by "Villeroy & Boch" - bathroom and guest WC tiled in granite - smoke detectors in all bedrooms - partly glass doors with fancy balcony railing upstairs - interior window sills in "Carrara-Bianco" marble - real wood veneer interior doors with "Sühac" stainless steel handles - electrical switch program by "Gira" "Everything is possible, nothing is mandatory... ...let your wishes run free."

Miscellaneous
Availability: construction time approx. 16 weeks after construction start
Floor plans and views may contain chargeable special components.
Turnkey building in the sense of this offer means: - including land - incl. developed basement without property-related costs such as earth, sewer works, and house connections
Floor coverings and painting/wallpapering work by owner

[ATTACH alt="Bauhaus-gira-Keller-Grundstück-Ausstattung-pumpe-74199-1.jpg" type="full"]3579[/ATTACH] [ATTACH alt="Bauhaus-gira-Keller-Grundstück-Ausstattung-pumpe-74199-2.jpg" type="full"]3580[/ATTACH] [ATTACH alt="Bauhaus-gira-Keller-Grundstück-Ausstattung-pumpe-74199-3.jpg" type="full"]3581[/ATTACH]

Surcharges not only make me gulp, but reach directly for resuscitation! Otherwise, the price is not assessable overall. Underfloor heating should actually be standard, [Kontrollierte-Wohnraumlüftung] I no longer want to miss.

I always have to laugh when I hear/read the argument for controlled residential ventilation in connection with allergies. In the very best case, I would accept that if it were (in my allergy case) surrounded by wheat fields all around, and if that were the case, I would not build my house there...

I also have problems, but so far I have grown up without such a thing. You simply cannot shut yourself in the house. Take the money saved and do proper desensitization!

Awareness? What exactly do you understand by that? Also consider controlled ventilation, but more for the sake of airing out!

18000 for earthworks including house connections I do not find excessive if stormwater drainage is also included - everything else yes, but many providers make their individual surcharges for the extras.

Regards Yvonne

Without claiming to be a great expert:

The equipment of the house is supposed to be upscale (I will copy the Immobilienscout listing at the end here.)

Only a gas heating system with radiators in the rooms is installed.
He said that if I want underfloor heating, it will be operated with an air heat pump.
Additional costs for this system + underfloor heating amount to about €15,000.

Upscale equipment and then with gas heating + radiators?

Costs for the air heat pump and underfloor heating - could be correct, since it is both together - but I haven’t dealt that intensively with air heat pumps. Surely others can contribute more experience here.

And he kept saying that this A-H-P would be some kind of solar technology?? Since it extracts heat from the air.

??? huh ???
That the pump extracts heat from the air is correct. But what does that have to do with solar technology?
Is that man really an architect?

Furthermore:
Additional costs of about €18,000 for earth and sewer works and house connections.
Is that alright?
He said that includes earth excavation and the connection laying from the street to the house. (Electricity, water etc.)

€18,000 should be fine - of course it depends on the plot, the soil, etc. Make sure that removal + landfill fees for the earth are included.

Another extra:
We could have a heat recovery system installed for about €15,000, with air filter and so on. So for allergy sufferers, like in passive prefab houses.
He estimates that would lower the KfW rating from 70 (which it normally has) to 55.
Is the additional cost + health aspect worth it?
I’m allergic to pollen and get extreme eye itching/burning, itching in the palate etc.

Then at that price it is probably a central ventilation system.
However, I doubt that KfW70 let alone KfW55 will be reached here (with the combination gas + ventilation).
According to what I read here last year, it is difficult to impossible to reach KfW70 with pure gas heating + radiators.
Ventilation with heat recovery does bring a small boost forward, but to my knowledge nothing decisive.

And finally:
The plot is located on a slight slope. That means about half of the basement is in the ground, or in other words, from the terrace a few steps down to the garden.
On the left side is the other half of the duplex, on the right side a stream, and behind the garden, directly adjacent without any gap, the forest slope goes up.
Occasionally some animal visitors. (according to neighbor: mice, 2 rats, marten nest somewhere nearby, fawn, wild boar)
How would you assess such a plot? We are basically city kids.

How high is the difference in elevation between the house/basement slab and the stream?
I always have in mind the pictures from a few years ago where, after snow melt and prolonged rain, small cute streams developed into rushing torrents. Directly adjacent is a forest slope. If the forest ground is not “absorbent,” the water from there has to flow somewhere too. We have a development at the foot of a vineyard - there a building without a basement or maximum with a waterproofed basement was recommended because the water could not seep into the vineyard soil.

Sounds quite negative from me now - it is not meant that way at all. Just to focus your attention on questions you should ask before you decide.