Disadvantages of a very narrow building?

Hello everyone! We are planning with an architect and planning to build a single-family house of about 140sqm (shed roof, without a basement). We have a plot of land (about 24x19m) that is oriented in such a way that if the house were placed normally facing the street, it would have a north-facing garden (the plot has the 19m side along the street). Now the architect has designed a really nice, "architecturally appealing" building for us, which is rather narrow in terms of building volume, with the following exterior dimensions: 5.90 x 16.15m, with the narrow side facing the street (thus facing south). Very narrow, but this way we can create a beautiful west garden with a great terrace. We like the floor plan, the room layout also accommodates everything as we like it. The roof would slope to the east. BUT: We are pondering the rather narrow building. After all, energy-efficient building is quite popular these days and we think the energy aspect should not be taken lightly. Reading on the internet, shed roofs, whether for energy saving or generation, are mostly oriented north or south. Furthermore, a narrow building tends to lose energy more easily than a more square one, right? Also, planning to install a solar thermal system on the garage unsettles us. Is all this worth the west garden? Or wouldn’t a completely conventional building be smarter after all?! If you need more information, just ask! Thanks already!

On the one hand, the energy efficiency of the building is calculated individually, so I wouldn't worry about that. On the other hand, a garage can also serve as a solar panel installation. I would be interested in the design and the location on the property. I roughly sketched it out and found it suitable. Nevertheless, 5.90 as an external dimension is quite extreme (I know these dimensions from houseboats), so I am interested in the room arrangements. If you like, feel free to obscure the architect and post the designs here or send them to me in a private message.

Good morning

We are also building an elongated mono-pitched roof house.
Not as extreme in dimensions as you.
Kfw 40 is the goal and with proper insulation and heat generation, it is also easily achievable.
Our roof and thus the living space faces southwest.
The thermal solar system is also on the garage roof, with the buffer directly underneath.

Site plan, floor plan, and elevations would also interest me.
My design can also be found here in the forum.

Olli

Such a house would be a no-go for me! Much too narrow! BUT: The north garden is really great. When you are at home in the afternoon/evening, the sun comes from the west and shines wonderfully into the garden. With a bit of creative garden planning, you can create a great sunny garden with matching terrace(s). I personally would not be interested in a south/southwest garden, because the sun always hits the terrace full on there. We ourselves have a north/east garden. The house is a bit quirky and has a west/north corner terrace. We can have breakfast in the sun in the morning and then (once the sun has gone around the house) have sun all day on one part of the terrace or in the afternoon on the entire terrace. Of course, it also depends on the neighboring buildings (a site plan is useful), but I think it is easier to play with the garden than to be annoyed later about a house that is too narrow.