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:
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?
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?
The B&J Jalousiecontrol II flush-mounted unit costs at least 80 EUR. For 19 roller shutters, that amounts to 1,520 EUR for the units. On top of that, an operating element is required, for example, a timer costs 65 EUR. So, if I want to equip all 19 roller shutters with at least a basic timer, that’s another 1,235 EUR. Altogether, that makes 2,755 EUR.
Is this referring only to the heating or also to the RTRs?
Mycraft schrieb:
Heating/ventilation is a topic on its own; you need to consider whether it even makes sense to integrate the systems into the bus. The gateways are often disproportionately expensive. However, this can also be done later if necessary. Just lay the bus cables and possibly NYM cables.
Is this referring only to the heating or also to the RTRs?
Why on earth would you want to connect all 19 roller shutters to a single timer switch? What’s the benefit?
Timer switches make sense where a) they are regularly raised and lowered, and b) this happens at predictable times.
Think about your roller shutters. How many out of the 19 are left for that?
It’s nice to see someone enthusiastic—I mean that sincerely. But you really change directions like others change their underwear.
And there’s more than just 0 and 1.
Timer switches make sense where a) they are regularly raised and lowered, and b) this happens at predictable times.
Think about your roller shutters. How many out of the 19 are left for that?
It’s nice to see someone enthusiastic—I mean that sincerely. But you really change directions like others change their underwear.
And there’s more than just 0 and 1.
By skipping timers, you save 46 EUR per control unit. Either way, the total cost will be somewhere between 2,300 and 2,800 EUR.
My opinion on automation hasn’t really changed. The shutters should always be electric and work with a simple press-and-go principle (not those long-press buttons that don’t actually save time, or rocker switches that have to be reset afterward).
Of course, everything should be compared now, but KNX might not necessarily be much more expensive after all.
So, I think I would like to cover the basic functions with conventional pushbuttons/switches (for example, in the living room, install a central control unit with 5 rockers = 10 pushbuttons for dimming 2 lamps and operating 3 shutters) and then parameterize it, maybe adding some scenes later once the living habits are better understood. Then also a central off function (for stove, oven, standby devices, lamps…). Maybe also a kind of window status indicator (possibly via server -> smartphone?).
More complex functions could be handled via the server, but the basic functions should always be operable even if the server fails.
Still, the question remains what else is needed for a complete KNX installation? For example, presence detectors: only in corridors? In corridors and functional areas (utility room, laundry room, possibly guest bathroom) or everywhere (which is expensive!)?
Or what should be considered regarding lighting? LEDs were quite special because of transformers, voltage, etc.?
My opinion on automation hasn’t really changed. The shutters should always be electric and work with a simple press-and-go principle (not those long-press buttons that don’t actually save time, or rocker switches that have to be reset afterward).
Of course, everything should be compared now, but KNX might not necessarily be much more expensive after all.
So, I think I would like to cover the basic functions with conventional pushbuttons/switches (for example, in the living room, install a central control unit with 5 rockers = 10 pushbuttons for dimming 2 lamps and operating 3 shutters) and then parameterize it, maybe adding some scenes later once the living habits are better understood. Then also a central off function (for stove, oven, standby devices, lamps…). Maybe also a kind of window status indicator (possibly via server -> smartphone?).
More complex functions could be handled via the server, but the basic functions should always be operable even if the server fails.
Still, the question remains what else is needed for a complete KNX installation? For example, presence detectors: only in corridors? In corridors and functional areas (utility room, laundry room, possibly guest bathroom) or everywhere (which is expensive!)?
Or what should be considered regarding lighting? LEDs were quite special because of transformers, voltage, etc.?
Mycraft schrieb:
As I already mentioned, mentally go through the rooms and note down which functions are needed. Not every room light has to be dimmable, and not every power outlet needs to be switchable. First of all, lighting, blinds, and room temperature control should all run on KNX, so everything is integrated into one system. Heating and ventilation might be less important? But they could definitely be retrofitted later since heating, ventilation, and electrical systems are all located in the utility room on the ground floor.
Then I would want to install, per room, a room temperature controller (RTR) plus temperature sensor and a multi-button switch. Basic functions like turning lights on/off/dimming or raising/lowering blinds should be controllable there. Since rooms such as the guest bathroom (including shower), utility/technical room, or laundry room will also have an RTR (or must have one), why not have 4–6 buttons there?
The most important thing for me is that the system can be freely configured later beyond these basic functions. That would be a key advantage. After six months, we might realize that during dinner we always use this or that light at a certain dimming level—I can’t know all that now. At that point, the system could be reprogrammed accordingly.
Another example would be functions like gradually brightening the bedroom light early in the morning and raising the blinds. This would likely run through a server so I can quickly set the wake-up time from my phone in the evening. But for this, no additional sensors, buttons, or actuators are needed.
So my question is: according to common opinion, which sensors, buttons, actuators, etc., belong to a "complete" KNX system? I mean things like blind actuators for all roller blinds, dimming actuators for all dimmable light sources, switching actuators for all switchable lights, switching actuators for all switchable power outlets, or presence detectors for hallways/stairs (or everywhere? But that would get expensive) or temperature sensors per room plus heating actuator.
I’m not talking about unusual things like occupancy sensors under the mattress—that’s more exotic. But blind actuators or dimming actuators are surely standard for anyone installing KNX, right?
And regarding lighting, I’m more confused now than before. Do you use 230V and retrofit fixtures, or a central transformer and then 24V to the lights? With some combinations, you can even adjust light colors, or is that just a gimmick? But you definitely can’t do that with 230V and retrofit, right?
EinMarc schrieb:
For me, there is one clear reason for KNX/central control that, in my opinion, cannot be beaten:
Central OFF at the front door
By now, I know too many tragic and sad stories of houses destroyed by fire where the owners were not at fault at all, so I want to avoid that as much as possible.I assume the two main appliances to be switched off centrally would be the cooktop and oven. But don’t those usually have timers? Or are there special cooktops without timers or with self-setting clocks?