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

Hello,

Yesterday, we met with an architect who showed us a plot of land for a semi-detached house. The other half is already built.
The house has 140 sqm (1507 sqft) of living space, although a large part of this already includes the basement, as it is usable living space (with a window).

The house will be finished to a high standard (I will copy the real estate listing at the end here).

The architect will act as the general contractor and work with local craftsmen.
For additional work such as extra electrical outlets, different bathroom fixtures, etc., I will need to contact his respective craftsmen, who will then provide me with the costs.

Now to the main questions:

The house comes only with a gas heating system and radiators in the rooms.
He said if I want underfloor heating, it will be operated by an air-source heat pump.
The extra cost for this system plus underfloor heating is about €15,000 (about $16,200).
This sounded reasonable to me as I didn’t have any idea before. On this forum, some people were shocked when someone had to pay €8,000 (about $8,600) more.
What do you think about my price?
Also, he kept saying that this air-source heat pump is a form of solar technology, because it extracts heat from the air.

Furthermore:
There are additional costs of about €18,000 (about $19,400) for earthworks, sewer connections, and utility connections.
Is this reasonable?
He said this includes excavation and laying the connections from the street to the house (electricity, water, etc.).

Another extra:
We could install a heat recovery ventilation system with air filters for about €15,000 (about $16,200), similar to what you find in passive prefab houses.
He estimates this could improve the energy efficiency rating from KfW 70 (the usual) to 55.
Is it worth the extra cost, also considering the health benefits?
I am allergic to pollen and suffer from extreme eye itching/burning, throat itching, etc.

These were my main questions so far.

Additional points:
I forgot to ask about the cost for electric shutters. What would you estimate?
And approximately how much would a garage cost?

Is a bedroom with a walk-in closet sized at 15 sqm (160 sqft) big enough? It seems a bit small to me.

Finally:
The plot is on a slight slope. This means roughly half of the basement is below ground level, or put differently, from the terrace there are a few steps down to the garden.
On the left side is the other semi-detached house, on the right side there is a stream, and behind the garden, directly adjacent without any gap, the forest slope goes up.
There is occasional wildlife visiting (according to the neighbor: mice, two rats, a marten’s nest somewhere nearby, a young deer, wild boar).
How would you assess this kind of plot? We are basically city people.

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

Here is the listing:

+++ NO COMMISSION +++ “BAUHAUS STYLE” IDYLL BY A STREAM – with Basement

Purchase Price:
289,820.00 EUR

Rooms:
5.0

Living Area Approx.:
140.91 sqm (1,517 sqft)

Plot Size Approx.:
420.00 sqm (4,500 sqft)

Main Features
House type:
Semi-detached house
Usable area approx.:
16 sqm (172 sqft)
Number of floors:
3
Bedrooms:
4
Bathrooms:
1
Guest toilet:
Basement:
TV / Internet / Telephone:
Electricity consumption: from 2,500 kWh*

Costs
Purchase price:
289,820.00 EUR
Buyer’s commission:
None

Building Quality
Construction phase:
House in planning (designed)
Standard of finishes:
High-quality
Heating type:
Central heating
Energy certificate:
Not yet available

Property Description
Idyllically situated by a stream, secluded at the edge of the forest, a planned, attractive detached family home with a basement will be built here, turnkey and solidly constructed. This spacious and modern energy-efficient house can be customized with the architect to meet your personal needs, including changes to the floor plan and finishes for your “dream home.” - the open living/dining area is spacious and bright with lots of glazing overlooking the garden and terrace - room layout changes possible - master bedroom with walk-in closet and two children’s rooms - daylight-filled comfort bathroom - generous living/work room in the garden-level basement

Features
“Masterful craftsmanship by local specialized tradesmen” - finished basement - energy-saving, breathable natural brickwork with additional external insulation for energy-conscious comfort - heating system with efficient gas condensing technology, optionally with solar collectors and underfloor heating - family-friendly daylight bathroom with tub and shower - ceramic sanitary fixtures by “Villeroy & Boch” - bathroom and guest toilet tiled in granite - smoke detectors in all bedrooms - partially glass interior doors with decorative balcony railings on the upper floor - interior window sills in “Carrara Bianco” marble - solid wood veneer interior doors with stainless steel handles - electrical switches by “Gira” “Everything is possible, nothing is mandatory... let your wishes run free.”

Additional
Availability: approx. 16 weeks construction time after start
Floor plans and elevations may include optional features at extra cost.
Turnkey means in this offer:
- including plot
- including finished basement without plot-related costs such as earthworks, sewer and utility connections
Floor coverings and painting/wallpapering work done by buyer

Surcharges not only make me gulp, but actually make me reach for the resuscitation!
Otherwise, the overall price cannot really be assessed. Underfloor heating should actually be a standard feature, and I can no longer do without a controlled ventilation system.

I always have to laugh when I hear or read the argument for a controlled residential ventilation system in connection with allergies. In the best-case scenario, I could accept that if the house (in my allergy case) were surrounded entirely by wheat fields, and if that were the case, I wouldn’t build my house there...

I also have problems but have grown up so far without such a system. You can’t just lock yourself away in the house. Take the money you save and invest it in proper desensitization!

Awareness? What exactly do you mean by that?
Also consider controlled ventilation, but mainly for the purpose of airing out!

18,000 for earthworks including utility connections does not seem excessive to me, especially if stormwater drainage is included – everything else does, but many providers add their own individual surcharges for extras.

Regards, Yvonne

Without claiming to be a big expert:

305er schrieb:

The house is supposed to have upscale finishes (I’ll paste the listing from the real estate site at the end here).

There is only a gas heating system installed with radiators in the rooms.
He said if I want underfloor heating, it would be operated with an air source heat pump.
Additional costs for this system plus underfloor heating come to about €15,000.

Upscale finishes, and then gas heating with radiators?

Costs for the air source heat pump and underfloor heating - that could be realistic since it’s both combined - but I haven’t really looked into air source heat pumps in detail. Others here might have more experience to share.

305er schrieb:

And he kept saying this air source heat pump was some kind of solar technology?? Because it extracts heat from the air.

??? huh ???
It’s correct that the pump extracts heat from the air. But what does that have to do with solar technology?
Is the person really an architect?

305er schrieb:

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

€18,000 should be about right – of course, it depends on the plot, soil conditions, etc. Make sure that removal and disposal fees for the excavated soil are included.

305er schrieb:

Another extra:
We could install a heat recovery ventilation system with air filters and such for about €15,000. Like those used in passive prefabricated homes.
He estimates that this could lower the KfW energy standard from 70 (which is normal) down to 55.
Is the extra cost worth it including the health benefits?
I’m allergic to pollen and experience severe itching and burning eyes, itching in the palate, etc.

At that price, it’s probably a centralized ventilation system.
However, I doubt that KfW 70, let alone KfW 55, will be achieved with the gas heating plus ventilation combination.
From what I’ve read here in the last year, reaching KfW 70 with just a gas heating system and radiators is difficult to impossible.
A ventilation system with heat recovery does provide some improvement, but as far as I know, nothing decisive.

305er schrieb:

And finally:
The plot is on a slight slope. Approximately half of the basement is underground, or in other words, from the terrace you go down a few steps into the garden.
On the left side is the other semi-detached house, on the right side a stream, and directly bordering the garden without any gap, the forested slope rises.
Occasionally there are visits from animals. (According to the neighbor: mice, two rats, a marten’s nest somewhere nearby, fawn, wild boar)
How would you assess such a plot? We are basically city people.

What is the height difference between the house’s foundation/basement and the stream?
I keep remembering pictures from some years ago when snowmelt and heavy rain turned small, cute streams into rushing torrents. Right above is a forested slope. If the forest floor is not very absorbent, that water needs to go somewhere.
Here, there is a development at the foot of a vineyard slope – there, they recommended building without a basement or at most a waterproof basement (“white tank”) because the water couldn’t soak into the soil of the vineyard slope.

Sounds a bit negative coming from me – that’s not my intention. I just want to draw your attention to questions you should ask before you decide.