Floor plan design for 2 small semi-detached houses according to KfW40+

Hello,

after my bathroom planning has pretty much failed, I am now trying to put the entire planning to the test. Today we went to our preferred construction company, with whom we will most likely build, and presented the plans as a planning basis as shown here (price for the shell including double-wing window, roof, tiles, insulation).

The construction company has no architect of its own, our cousin (architect) is unfortunately fully booked and could only start next year..., we will contact other architects next week. Possibly, a solution for a "cozy" floor plan that is not so convoluted will be found here by then. Fewer walls/corners, everything should still fit in. I hope I have entered all the necessary information below?

Development plan/restrictions
Size of the plots - 308m² + 338m²
Slope - no (slightly rising towards the north, max. 1m over 28m depth)
Floor area ratio - 0.4
Plot ratio - 0.8
Building window, building line and boundary - drawn in or visible in the development plan
Edge development - yes, boundary distance to the north 4m
Number of parking spaces - 2 (per plot)
Number of floors
Roof shape - Gable roof with approx. 50cm roof overhang
Style
Orientation - ridge from west to east
Maximum heights/limits - eaves height: 4.5m, ridge height 9.0m
Further specifications - dormer max. 50% eave length and 1.5m below ridge

Requirements of the builders
Style, roof shape, building type
Basement, floors without basement - 2 floors
Number of persons, age - left: 2 each, right: 1 each
Space requirements on ground floor, upper floor
Office: family use or home office? - none
Overnight guests per year - 15 (small children => sofa bed)
Open or closed architecture - preferably open
Conservative or modern construction - modern
Open kitchen, cooking island - open kitchen-living areas
Number of dining seats - left about 3-4, right about 2-3
Fireplace - no
Music/stereo wall - yes
Balcony, roof terrace - uterraces at the bottom, dormer above (left 4m, right 3.5m) with a protruding balcony
Garage, carport - no (technical building external / mono-pitched roof)
Utility garden, greenhouse -

Further wishes/special features/daily routine, also reasons why this or that should or should not be

House design
Who designed the plan - Currently: "Do-it-yourself", possibly an architect will take over if it is not possible to make it suitable.

What do you especially like? Why? - I can well imagine living in it…

What do you not like? Why? too convoluted in the utility room area / bathroom, also upstairs the stairs to the attic are difficult
Price estimate according to architect/planner: - for the shell including double-wing windows, an offer will be available by the end of March (based on the plans shown here)

Personal price limit for the house: not sure yet (open for almost everything).[ /I]
Preferred heating technology - [I]heat pump, photovoltaic + battery, controlled residential ventilation, underfloor heating, possibly cooling via underfloor heating (GRK possible?)

If you have to waive, which details/extensions
-can you do without -
• large glass sliding element on the right ground floor (owner’s use) possibly omitted due to KfW40
• instead of very high-quality furnishings with inventory (kitchen, bathroom, living room) it may also be quite simple (but good).
• possibly the expansion of the attic (which is not allowed to be officially rented anyway)

-can you not do without:
• Bathtub
• Washing machine must not be in the bathroom
• Part of the controlled residential ventilation system is also located in the utility room, so the utility room on the ground floor is indispensable, the controlled residential ventilation system on the upper floor is in the dormer of the attic

Why did the design turn out as it is now?
Various designs were discussed within the family circle (some are currently building themselves, some are building services planners), discarded and redesigned until it technically fit and we liked it - except for the minor "details" mentioned below

Since the bathroom and kitchen of the two semi-detached houses are located on the central wall (fire protection wall), it would be nice if the basic position did not have to be changed completely.

What is the most important/basic question about the floor plan summarized in 130 characters?
• Alternative to the very convoluted utility room / bathroom solution (expensive, tight) while the open kitchen should "roughly" remain as it is. I like it because of the terrace facing south in front of kitchen and living room.
• better stairs solution
• missing storage space on the upper floor

Plans will follow shortly…

It is about the two plots at the very top slightly highlighted in yellow


Building envelope

After more than 30 years, I tried AutoCAD again, so please forgive any technical errors in the drawing.

This will also be my first self-built house; I bought my old house from my parents over 20 years ago (older than 250 years, pictures of it are in another thread ...). So also here: No real expert knowledge available (despite training as a draftsman and about 6 semesters of civil engineering :-/).

Oh, the terrace is not included yet: facing south across the entire width with about 3m depth, material partly stone slabs, partly wooden planks. The garden is small, I like to use the terrace or a deck chair on the small lawn and in the summer I usually only read on weekends. If everything goes well, I could also imagine a small outdoor sauna ([Saunafass]) for max. 2 people.

... by the way, it currently only concerns the floor plan on the right. My brother is building the left side, and he is still optimizing it. However, if there are good suggestions for that as well .... very welcome

Both residential units on the left are intended to be rented out, by the way. I will move into the ground floor on the right (alone), and the upper floor is also to be rented out here.

I am also quite aware that small, high-quality (KfW40+ = expensive) built apartments do not yield an "economic" return. Fortunately, that is not my focus.