ᐅ Is Smart Home KNX Automation Possible Based on the Floor Plan?

Created on: 27 Aug 2016 00:02
G
Grym
Ok, now let’s think about the topic from a practical perspective. I’m quite familiar with KNX, but I can’t really come up with a scenario where KNX would clearly benefit us. Here are our floor plans again:



Floor plan of a house with terraces, garden, multiple rooms, furniture, doors, and dimension lines.



Floor plan of a house with several rooms, doors, windows, and dimension details.


According to the current planning status, roller shutters will be installed everywhere (current planning status!). There will be a large sun sail to shade the central window and the dining room window from the sun. The dining room window facing east and the kitchen window will be in the shade shortly after noon.

A heat pump with cooling function and a ground loop exchanger for the controlled ventilation system are planned. Simple logic functions, such as bypass for the controlled ventilation or controlling the underfloor heating based on outside and return temperatures, are handled by the devices themselves. In winter, when the sun heats the floor, the return flow temperature rises, and the heat pump realizes it needs to heat less because of the external heat input. The ventilation system detects when the bypass should be activated.

Individual room control is pointless, or so everyone says in the pink forum. At least for our KfW55-standard building, it’s probably very unnecessary. Night setback is also not needed.

Energy-saving functions don’t interest me because the investment cost will always be higher than the electricity savings. Conventional smoke detectors will be installed, and please no hysterical discussions about this. There will be no gas, oil, or fireplace in the house. And if the house burns down while we’re away, it’s insured. There will be no photovoltaic system, and I’m not interested in any other extreme energy-saving measures. The washing machine has its own timer. Usually, we just load it in the afternoon and hang the laundry in the evening. It doesn’t need to run for three hours at night because of lower tariffs to save 0.3 cents per wash cycle.

The living/dining/kitchen area will have six roller shutters and four dimmable lights. Three shutters and two lights each will be controlled from switches next to the living room door and the kitchen door. The switches are arranged side by side so that the leftmost switch controls the left side of the room, and so on. So the west, south, and central living areas are controlled from the living room door; the south dining area, east dining area, and east kitchen are controlled from the kitchen door. For shading, only the two roller shutters next to the living room are relevant (south living room, as it is not under the sun sail, and west living room).

Currently, in the old building, we have internal blinds and a large west-facing facade. Apart from the five warmest days of the year, we don’t fully shade the windows. We just want to avoid direct sunlight where we are sitting, working, playing, etc. Depending on the situation, some blinds go up and others go down, and so on.

Constant light regulation is not desired. Even now, we switch lights on and off based on feeling. When we want to go to bed soon, the lights are usually off or more distant lights are on (kind of indirect lighting). I have different lighting preferences than my wife, and when we are together in the room, naturally, a compromise solution applies.

I sometimes work flexible hours, and sometimes I might sleep only four hours one night and seven hours the next day. A rule like “dim after xx o’clock” won’t work.

There is no defined TV lighting plan. It depends on the program. For briefly watching the news, all lighting can remain as is. For a moderately interesting football game, only the direct light is turned off, but indirect lighting can stay. For a ‘Game of Thrones’ episode or a good movie, everything should be off, especially since these often have dark scenes. Sometimes, for example, the hallway light stays on as indirect lighting for the living area (which makes sole hallway lighting with motion sensors pointless now).

Hallway lighting will have switches (two-way switches) next to each door, which can turn the lighting of the respective floor on and off. So yes, exactly one switch next to each door. The two lamps upstairs will switch on and off simultaneously. It is a floor-level switch. At stair landings, of course, there are exactly two switches: one for upstairs and one for downstairs. So, coming down the stairs, you can operate both switches to turn lights off upstairs and on downstairs. Or you turn off the upstairs light at the bottom of the stairs (top switch off = upstairs off; makes perfect sense to me).

Stair lighting could theoretically be controlled similarly, but that also depends a bit on the show effect, right? It could also be done with a timer or motion sensor. And if pets trigger the stair lighting, well, that’s just how it is. At the moment, we don’t have pets.

As for roller shutter control in the living/dining/kitchen areas, as I said before: short press for fully up/down and hold for precise positioning. But half-positioning is discouraged because temperature differences across the glass can cause damage. For example, next to the living room door, pressing the button three times briefly will raise (or lower) the three shutters. All other roller shutters follow the same principle and are arranged next to their respective doors. Only for bedrooms could I imagine a switch with a timer function, and I would only program the opening time for the next morning. I don’t need a closing time. A short press closes the roller shutter. But if I set my alarm clock to 6:53, I also set the roller shutter to 6:53 so that daylight wakes me at the same time (in the future, we will have joint wake-up times again, and my wife won’t have shift work anymore). BUT: all this can be done conventionally and very simply. So: the office (guest room), bedroom, and two children's rooms will have a switch (short = fully up/down) that allows an opening time to be set.

Just to summarize the shading logic during the day: roller shutters go down in the morning when leaving the room/living area and stay down until the first person returns home in the afternoon. This covers the first 10–12 hours of sunlight exposure.

The lighting in many rooms will be dimmable, but I don’t want expensive color lighting effects. The bulbs should have low blue light and good quality.

So, I think I’ve described the most important areas: roller shutters, lighting, heating, and a few other things...

How can automation like KNX help us now? What comfort gains are possible? What should we automate and why?
Uwe8230 Aug 2016 11:15
Tom1607 schrieb:
That’s exactly how it’s done. But since I assumed the original poster only needed this for “understanding,” I didn’t go into much detail

That probably would have been one of the next questions. Two days ago the OP wasn’t even considering KNX for their own house, and now they’re already asking where to connect live and neutral.
Tom1607 schrieb:
I have six in my setup. One RCD for lighting, one for kitchen cooling appliances/freezer, one for outdoors, one for sockets/roller shutters, one for kitchen, and one for the internal distribution panel

That’s also an interesting approach. We have one per floor, one for outdoors, one for heating, and one for the garage. It also made planning the terminal blocks easier.
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Sebastian79
30 Aug 2016 11:22
You need to get to know Grym better – that’s just how he is. For me, this is heading in the completely wrong direction, as the horse is being saddled from the wrong end.

Apart from the garage, our setup is like Uwe’s – I actually wanted a French-style wiring system, where lighting and sockets are separate, but somehow that got missed.
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Tom1607
30 Aug 2016 14:02
Sebastian79 schrieb:
You need to get to know Grym better – that's just how he is. For me, this is going in a completely wrong direction, because it’s putting the cart before the horse.

Well, I’m just trying to explain the basics, offer some suggestions, and point out incorrect statements. One of the biggest misconceptions is still that KNX is expensive. Anyone who understands the fundamentals will realize that the additional costs for functionally comparable equipment are, if anything, only slightly higher. It only gets expensive with unnecessary luxury features, which then have nothing to do with comparable functionality – it’s like comparing a duck to a Lamborghini.

Whether or not to choose this is a decision everyone has to make for themselves.

In my opinion, if you’re building new, you should definitely install a bus system like KNX. I also tell everyone who asks me that they should run at least one IP cable in EVERY room, because that’s the future. Whether it’s television, phone, or internet, it all runs through that.
Sebastian79 schrieb:

Except for the garage, our setup is like Uwe’s – I originally wanted a French wiring system where lights and sockets are separated, but somehow that got overlooked.

Separating lighting and sockets is a must for me. What good is it if the RCD trips on the ground floor and I’m left in the dark without power across the entire level, while the upper floor still has electricity?

The highest likelihood of an RCD tripping comes from sockets. A defective or damp device can cause the RCD to trip. At least in that case, I won’t be left in the dark.
Uwe8230 Aug 2016 14:10
Tom1607 schrieb:
Separating lights and sockets is a must for me.

But what good does it do if the RCD for the lights trips? Then you’re really in darkness throughout the entire house. It’s enough to connect the neutral and protective earth when installing the lamps and suddenly… it trips.

I have the lights wired to circuits per room, with the entire upstairs hallway on one RCD. The chance of a short circuit there is smallest, and then you still have light if the RCD on the ground floor trips. So you can at least make it to the fuse box in the daylight.

On the other hand, if one trips in a room, at least I notice immediately because the light goes out in that area.
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Sebastian79
30 Aug 2016 14:11
Well, the situation with the RCD is like this – I don’t find it too dramatic, though it would have been nice to have it. This case is quite rare, and if it does happen, there are flashlights or the other floors provide light. In the end, it’s one of those constructed issues.

You are probably somewhat right about the additional costs, because what it offers usually costs as much or even more when done conventionally – if it’s possible at all.

But that’s the problem with you “enthusiasts”: it’s considered part of new construction – just like all houses without a walk-in shower are seen as very poor quality. It’s not actually a requirement, and a house doesn’t become less livable because of it – which I notice in many posts here. Whether this is stated consciously or unconsciously, it always bothers me a bit.

Still, I think it’s great how you provide information here – even if the questioner is still approaching the issue the wrong way.
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Tom1607
30 Aug 2016 14:25
Well, not in my case. I have only one floor for living.
The upper floor is an office with its own supply and distribution, including separate RCD circuits...
There is no basement either. I don’t need one because I have a spacious floor area, and one has to be modest.