Floor plan design single-family house approx. 134m²

Is this forum here to help and exchange ideas, or to attest that people do nothing at home?

You are the first to say that you can do without storage space. The only way to explain that is that you do nothing at home, not even change batteries.

You should maybe just consider that a house is not only for watching TV and cooking, but you also have to store many everyday items that additionally require some room to maneuver when handling them... and that is not only tools. Whoever does laundry does not do it on half a square meter. And they know that too. If you ask Google how much space is needed for technology, you can very quickly come across just 2 sqm. The experience is simply that craftsmen have to get to the devices, sometimes with tools, in front of the electrical cabinet there needs to be clearance space, and shelves for household items just have to be placed somewhere. You can slide beverage crates under the stairs, but that space should not be counted because it is not walkable. Small tools are also needed in the house, even when there is a snowstorm. Then they are stored somewhere during that time. But well, probably neither the forum nor I help you at all, in your eyes now.

Yes. Although silicone is generally not stored over the winter because the manufacturer stamps a rather strict "use by" date on it, which should be adhered to chemically with silicone. Paint is also stored in small quantities, ideally just a small bucket per color for touch-ups. If the paint is mixed by the manufacturer, you can get the exact same color even after 25 years.

And... adhesive tapes, batteries... do you seriously believe every craftsman on this planet empties their vehicle daily and stores the tools in the heated workshop? Our installers keep their tools in the car 24/7. Battery, adhesive tape, this and that. In frost during winter, in heat during summer, in wind and weather.

As a cellar replacement, the storage room behind the garage is planned; it is 2sqm larger than our current cellar. Of course, you can’t make big leaps with that, but - drumroll - cordless screwdrivers, drills, etc. (Bosch and Festool case system say hello) have plenty of room.

I’m not a tool expert, but if you don’t heat, insulate, and keep the room dry, I think everything will just rust away. In the garage and similar places, you can really only store things that are weather-resistant.

I don’t know if it’s still possible with the current planning to insert an attic in the upper floor; that might be an alternative.

That’s not worth it, you can’t stand upright in the peak.

And what do you research on the topic of the technical room --> for example, by asking Google how big a technical room for a single-family house with a heat pump should be and then looking at a few different manufacturers’ sites. But I’ve also taken from that that I need to take a closer look at this topic.

It’s best to find the dimensions of comparable devices and place them to scale in the technical room. Make sure a technician can approach the device from multiple sides in case a repair is needed. Also, include all connections with the required minimum clearances.

I am not a tool expert, but if you don't heat, insulate, and keep the room dry, I believe everything will just rust away. Only things that are weatherproof can really be kept in garages and such.

Yes, of course that works. There are many craftsmen's sheds that are not heated. That used to be common. You store things there and also pursue a hobby. But you also have hammers, screwdrivers, and the like in the house. You want to have a house that is functional and offers space where you need it. And that is, of course, not outside nor in the attic.

Yes. Although you don’t store silicone over the winter anyway, because the manufacturer stamps a pretty tight "use by" date on it, which you should also adhere to with silicone, due to chemical reasons. Paint is also stored rather sparingly, at best a small bucket per color for touch-ups. If you had the paint mixed by the manufacturer, you can get the exact same shade even 25 years from now.

And... adhesive tapes, batteries... do you seriously believe every craftsman on this planet empties their vehicle daily and packs their tools into the heated workshop?
Our fitters keep their tools in the car 24/7. Battery, adhesive tape, this and that. In frost in winter, in heat in summer, in wind and weather.

When you start a paint, you don’t throw away the rest and keep only a small jar, but the whole container. Silicone also stood for acrylic and similar materials. And sometimes you buy one tube too many, which then often lasts for years.
Sure, that’s how craftsmen do it, because there is no other way. As a private person, you do it differently. Because adhesive tape is not used up as quickly as it is by a professional. And batteries are supposed to last longer due to less frequent use.

I’m not a tool expert, but if you don’t heat, insulate, and keep the room dry, I believe everything will just rust away. In garages and such, only things that are weatherproof really belong.

The important thing is that the room is dry. For that, it doesn’t have to be insulated and heated, just properly ventilated. Anyone who does more than just hang a nail in the wall has a workbench and tools, screws, etc. in the basement or shed. Only the batteries benefit if they are stored inside during the winter.