All About KNX Weather Stations - Talking Smart Homes with: Bastian Elsner

In our second episode of Talking Smart Homes, we are discussing the importance of weather stations in smart home automations with Bastian Elsner of Elsner Elektronik.

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Hello everybody! Welcome back to another episode of Talking Smart Homes I'm your host, Satja Lumbar and joined today with us is mr. Bastian Elsner. Hi Bastian!

Hi, thanks for having me!

Thanks for being here, and in today's episode we'll be discussing weather stations. A device fairly common in a modern smart home but also fairly complex to integrate. But before we start; why don't you tell us something about yourself, about Elsner Elektronik?

Sure, sure. So my parents founded Elsner Elektronik 31 years ago, and weather stations are actually one of the first devices that we ever manufactured, so yeah, in my family there's combined a couple of decades of knowledge regarding weather stations, so i'm really excited to talk about this topic today, and can't wait to get into it.

Well, we're all excited so great! Let's talk about weather stations. Would you say a weather station is an essential device in a modern smart home, and you know, based on what should people decide whether they should include a weather station or not, and what sensors should be included in a typical weather station?

All right, thank you for the question. So first of all, yes, in my opinion it is essential to have a weather station in a modern smart home, and as some guideline for people; if they don't know if they should use a weather station or not it's fairly simple. As soon as you would like to automate your shading, you should have a weather station. And the most important sensors for the most common functionalities that I would also recommend to always have is: sun, rain, wind, and temperature. Those four are the most important and most basic sensors that every weather station should have.

Well, thanks for this answer, and following up on that on that, you know, there's a huge range of weather stations on the market. And you know to the untrained eye,
they all look very similar. But if you look at the prices they can range from a couple of hundred of euros to a couple of thousand. What is the difference between those weather stations and what do you think is the optimal cost-effective device for, you know, a typical family house?

Yes that's a really interesting question that I have to answer in my day-to-day work quite often. So one of the factors that lets the price jump a lot is actually the measurement accuracy. So you have a lot of weather stations that claim to measure the same things but one does it a little bit better than the other, and there comes a price difference from. So for example, some weather stations, where the station have one sun sensor and another one has up to five sun sensors, in order to be as exact as possible where the sun comes from and which strength, so in it's measured in lux so how much lux you have, so this makes a huge difference within the pricing of weather station. Also the construction of the weather station and the design itself, to be quite honest a weather station is something that you see a lot, because it's on the facade. It can ruin the appearance of your house, so also design is an important aspect and the better the design mostly the more expensive the weather station is. Regarding to your question about the weather station for a family house, I would say, or in my experience, a weather station with a price range between 500 and 800 euros should be suitable, and should have everything you need when you're thinking about a weather station.

Okay, thanks for this answer. What about the use cases, you know, you already touched on the smart shading before, and I know also in the sales process when you're selling a smart home, we normally talk about protection of shades against strong wind, and using the sun intensity to also work with the heating algorithm, and is there some other use cases that you feel like are worth mentioning?

Yes, yes there are. I feel like you mentioned the most important ones, so there's definitely the automatic shading, and also the energy saving capabilities of the use of weather station, like the passive heating or also the passive cooling in the summer. For example, that can be realized with the temperature sensor in the weather station. Some more functionalities that you did not mention yet is for example the night closing. So this is basically also some sort of security function that can be realized with a good weather station. Also you have the twilight circuit so if the twilight appears you want the slats to lower, or you want to have the facades to be closed. Also what for me a weather station and the use of a weather station in smart homes provides some sense of luxury, because you can truly create a feel-good climate also during the day, because you can adjust the shading and the slats of the facades in a really exact way, so there's no need for you to stand up and control the facade by yourself, because the building is actually thinking for you. You don't get blinded if you're watching in front of the TV, you can set up so many things that just increase the comfortableness, and the luxury, and the comfort of your own home by the good use of a weather station. So really multi-purpose device.

What about watering the lawn?

Excuse me?

You know, watering the lawn? So for example, if you see that it has been raining for a past couple of days, then you turn off the the lawn watering mechanism.

Yes that is something that you can definitely realize with communication objects. It's the "senses", it's the "eyes" the "ears" the "smell" the "feeling" of your house. Basically, the weather station provides the "senses" to everything that happens around your house, and the automated shading is something that can definitely help you with that, and also the automated watering like you mentioned. Those are all functions that can be realized with the help of a weather station.

But if you would ask like, a complete layman, like you know, somebody who doesn't know what KNX is, somebody who didn't build a house yet, and you would ask like: what's the purpose of the weather station? He would say probably "it's knowing like what the weather is like, and what it was like in the past" and so on. Do you think that displaying the sensor values like the wind, the temperature, and so on is essential for the end user?

That is definitely something where we could start a discussion but I can talk from my personal experience. Every morning I get up I go to my room controller in the kitchen for example, and I just love observing what temperature it is in the morning. It's just great! I also take my bike to work so I know exactly; okay do I need an extra pullover, do I need an extra big jacket or is it fine? And this is the data the data I display in my smart home system. It's basically coming from the weather station, and from the sensors, and for me this is really interesting. And I look at it every day, several times a day. So if you ask me if it's essential to present this data? I would say yes. Also another fairly simple and straightforward reason is; you basically want to know if your weather station is working. If it displays all the same values all the time, you're like: "Okay is this thing that I installed on my roof, is it really working?" So for me those are all really straightforward reasons. But it really enhances my living comfort knowing those things, and yes I think it's essential for the end user to see those values, yeah.

And if you go windsurfing you have to check the wind right? :)

Of course, of course!

Okay. Let's talk more about the shading algorithm, because I know this is the most important function of the weather station, and I also know that a lot of integrators are struggling, you know, with setting up the the weather station. What would you say are the crucial parameters and what should the integrator be mindful of when programming or installing the weather station?

Okay so first of all -  location is everything. Understanding the the factors of the building, where you want to install the weather station. So before jumping right into the actual parameters, and into the settings of the weather station, it's important to really understand how the building is working, and how is it influenced by other buildings that are surrounded. And with this knowledge, if you have it, then you look into the into parameters. But if you just jump right into the parameters and you don't know anything about the situation, the surroundings the weather station is in, it will definitely get really complex and can also be sort of frustrating because some weather stations have up to six thousand parameters that can be set. But it all becomes really logic if you understand where you really want to install the weather station. So first, surrounding, then parameters.

And who is actually responsible for determining the location of the weather station? Because I know a lot of times the architect will say like: "Yeah it cannot be there in in this position because it will ruin the facade." So who is really responsible? Should an integrator be responsible, or should there be like an electrical designer, or somebody else who says: "Okay, the weather station must be here" and then if there is some damage or some unforeseen or unwanted consequences - who is the guy that is responsible for all of this in your opinion?

I wish there was a simple answer, I would really benefit from this answer as well. But in fact it's so different from project to project, as you rightly mentioned, sometimes you have an architect that does not want to have his facade ruined by the appearance of a weather station. Then you need to find a workaround. For example, if you have a flat roof you can basically install it on the roof. But coming back to your question: usually the electrical planning will only say "Okay, in order to achieve this functionality, this high level of automation of the building we need the weather station" and in the end it's a system integrator or even the electrician that needs to choose the right suitable spot to install it. For me there's a really easy rule where to place a weather station, it's super straightforward: so it's basically everywhere where the weather station can get hit by rain, sun, temperature, and wind. It's perfect situated, so on top of the roof is always a good spot, as high up in the building as possible is always good, because then the exposure is basically the highest.

But what about, for example, in the multi apartment building? So for example, you have some apartments in the first floor, and then you have you know... so in case of multi-apartment buildings: can you use just one weather station or should you use more weather stations? And you know, how many and let's say we have a case of like 200 apartment six story multi apartment building. What would be the difference here? How should one approach this kind of situation?

So, for a really large building, a complex with a lot of apartments let's come back to the example of 200 apartments. It depends on the shape of the building, it depends how many facades can be controlled. If you basically have a square building, so you have four facades, one weather station is actually enough. It doesn't matter if there's 500 apartments inside, one weather station is enough, because the location of the sun will always remain the same for the same building. So that is not an issue.

But what about the wind?

Exactly that's what I wanted to talk about next. Because one weather station is enough for the automated shading but the wind, the bigger the object, the more different is the wind, especially when we're talking about high buildings. So you mentioned the six story building - the wind will be tremendously different in the sixth floor than in the first or second floor. So I would definitely recommend to implement a lot of wind sensors, but simple wind sensors without the functionality of a real weather station will be sufficient. So six stories, 200 apartments, if I imagine a project like this, probably four to six extra external wind sensors plus one weather station and you have the same functionality. Because the biggest risk for the shading and the slats is the wind for sure, it can do the most damage.

So basically, you can separate, so have a just a separate wind sensor without the sun sensor, and the sun sensor in a different location. Do you think that's also an approach that could be utilized in a family house? Because, for example, for the sun you can put it on the roof ,but for the shades it can it can be better if the wind sensors is in a different position. So would you say that approach would also be sensible for a family house? To have a separate sun and wind sensor?

If the weather station is installed correctly, and if we're thinking about I would say standard to big size family house ,the weather station is sufficient. There is no need for another wind sensor, that is my opinion. If we're talking about some sort of palace family house that is just extremely huge - as soon as the size comes into play of a building then it would be good to at least think about a wind sensor but almost all the family houses I've seen in my life would suffice a simple weather station, it would be enough.

Okay thanks! Now let's move on to a little bit different topic. So there's a lot gadget IoT, DIY weather stations on the market today, like for example the Netatmo weather station, and there are some more products and those can also be integrate integrated for example to KNX via smart assistant like Apple Home or something else. So what would you say is the main difference between a professional weather station like the ones that Elsner is producing, and like a DIY weather station like the one that I already mentioned?

Yes, so the biggest difference I would say it's - I would just call them for now IoT weather station and professional weather station I hope that's not to biased for the listeners - but the biggest difference in my opinion is that the actual measuring is taking place in the device in real time, exactly where the control needs to be done. If you perceive all this data, you can also get those the same data within Netatmo as an example, or just in general IoT weather stations, you have it for an area. So if you have a cloud, like a really local rain it's possible that your IoT weather station is saying it's raining, but it's raining 500 meters away or only 200 meters away, but your house is actually not hit, so you don't want anything to be controlled. That is one thing. Also the automated shading is really hard. It can be controlled with an IoT weather station, but not to that level and to that degree of automation, and of that quality that it can be done with a professional weather station, because you don't have the real time measurement, because the weather measurement points where the Netatmo or the IoT weather station gets the data from, might be somewhere else, like a kilometer away or two kilometers away. But you want the data on your house, you want to have it as exact as possible, and for me that is the biggest difference: It's the quality of automation that can be achieved with a professional weather station, versus an IoT weather station.

So basically, if you're building a KNX home, the professional weather station is something that you would recommend right?

Yes, I would definitely recommend that, and not only because we are a manufacturer. It's also just, if you really take the money in your hand you're building a house, and you would like to automate your house, don't save on the weather station. There are so many on the market and so many manufacturers that don't do anything else except of weather stations since centuries, and the quality is so good, that also the lifetime is really good, and the value, it might seem really expensive in the beginning, but if you look over the lifetime and the quality of life that can be achieved through that automation, you will say it's worth it. And yes, that's my recommendation. If you take that much money in your hand to automate your home, don't save the money on the weather station, it's not the right place to save money in my opinion.

Probably this will apply also to my next question. You know, what about the weather service? Because it's much less complicated to install, no cabling, it's also cheaper, and also it can act preemptively, because of the weather forecast. So, like, why not close the window before the rain already starts pouring in? So do you have an idea about that or?

Yes, yes. Let's come back to the automated shading, and I will also include your windows open and closing example. So, if the weather service is saying it's raining, it does in fact not need to be raining in your position. I'm sure we all realize that we check the weather forecast on our phone, it says it's actually raining or it says it's gonna rain, but I'm looking up to the sky, and I'm asking myself: "Okay, where is the actual rain?" Your house does not know that, because you have the senses, you see, and feel if it's actually raining. But your house is lacking of those senses without a weather station. And we all know this example, that the weather forecast is not as true as we'd like it to be.  That also applies for the control of your house. You don't want all the windows to close because the weather forecast is saying it should rain but then it's not raining. And you don't want all the controls to start to drive up and down the slats. You don't want it, you want those things to happen when there's an actually need to control and automate things. There's just a larger room for a mistake in order of the weather in comparison of the weather station to the weather forecast. So it's coming back to the measurement quality, because that's the most important and the biggest aspect. Also, for the pricing of the weather station, the measuring accuracy needs to be there as exact as possible, where the control needs to take place, and usually the weather forecast is not measured where your house is. It might be close, really close, but it's not on your roof where the control needs to take place.

Yeah, so similar to the IoT stations right?


But there's another question here. Because, you know, relating to what you said, I agree that there's a big problem for the users if something happens, and there's no real reason for it, like you said like, you know, it's raining like maybe a kilometer away, but the window is closing. So I know that users really hate it, but in case of a professional weather station I think it can also bother the users. If you know things are happening, for example, I just come from the toilet I'm not dressed and everything, or even worse, my wife comes from the toilet, and then the wind becomes strong, and the shade goes up. So what do you think? Should the professional weather station be active when people are not at home, or all the time? How how would you avoid those kind of cases?

So the use case that you described to me is really, really easy to solve with the parameters, where you can set up a professional weather station. So basically, if you want to trigger a wind alarm you can say "Okay the wind needs to be constant for, let's say 20 to 30 seconds over a specific wind speed, and if that is given then you go into an alarm position and you drive them up. But if there's just one quick wind that is really fast, but only for one or two seconds, a good automation with the weather station should not do anything. You always need to have it for at least repetitive. So if there are some irregularities, some a normal anomalies in the measurement, the weather station should understand that. And that can be set, and it's usually one of the basic configurations, that you already have within the parameters. So it's a basic setting. Those are issues that I don't really think they can come up with a professional weather station.

Maybe I should use a different example: you know, like, I  was thinking , we have a family breakfast, and the the sun is strong, but then a cloud comes over, and you're eating but then suddenly the shades close because of the intensity of the sun, and because you want to prevent the overheating. So should we disable that and only use the smart shading when people are not eating ,or when they're not at home?What do you think about this?

I mean it's... you can always integrate some sort of a blocking function, so that if you're having a family dinner, and you just want to have everything like it is right now, you can just disable the functions. You can set the timer for half an hour, 45 minutes, an hour, it's up to you. Usually you control that within the KNX system, I know it, you can control it. So, a good smart home system will always allow the user to be more powerful than the automation, because it's not the automation that should control the way you're living - it should always only be something that enhances your comfort. And if you just need to press a single button or control it with your phone, okay, now disable automation because I have a family lunch and I don't want to be disturbed by any blinds going up and down, windows closing and opening... That is always an option. But I have to come back to the other example, because it's the same. You don't want to have any automation triggered because of one thing, because of one measurement -  you always want to have several measurements in a short amount of time in order to trigger an action. So, if a cloud is flying by, it should not do anything, because the time frame in which the cloud is not there, should not trigger anything. That is done by the algorithm and the programming of the weather station, so it only sends real data that is important for the automation controls, and not the data that goes out of line like you mentioned. The example of strong wind or one cloud that is passing by; this is prevented by the technology in itself.

All clear, thank you, for this really precise explanation. What in your opinion are the biggest mistakes that an integrator can make when installing a weather station?

Yeah it's a good question, and I almost have to laugh, because it connects to another question that you asked me earlier: who decides where to install the weather station, and also what is the where is the best place to install a weather station? And in my experience that is the most common mistake. So I really often see that some installers, some electricians, or even end users install the weather stations under the roof. For example, because they don't want their beautiful expensive weather station to get wet - but that doesn't make sense! Because you can't measure the rain if you hide it from the rain. So the best is to put it in the exposure, as mentioned before, but most people try to hide it somewhere or take away the exposure, and that also takes away all the capabilities. I put up the example or the comparison; it's the senses and in order to feel anything, in order for your senses to recognize changes in the environment you need to see, feel, smell, taste, whatever, to chase those changes. But if you hide it away, if you wear some glasses that blind you, you don't see, and you don't have those senses. The exact same thing applies to the weather station: put it out in the open and don't hide it anywhere. In my experience that is the most common mistake.

So basically: location, location, location right?


Do you have any other advice for the integrators?

Yes, in my opinion, some integrators are sort of afraid of the use of weather station even though it gets more and more common. But for the integrator, and the installer, and also the end user it provides a real added value, in my experience, because it makes your whole installation better. We only talked about a few aspects of the weather station and there is way more - there's a world to it, and all the manufacturers, especially in the KNX world, or in the BUS system world for the smart homes, they improve the functionality, and the options you can achieve a lot -  day to day. And the weather stations have become definitely a key aspect. So if you want to make a difference in your installation, and you want to give added value to your customer; always propose a weather station, and try to get up to speed if you're not aware of the possibilities that you have with the weather station. It's worth it in the long run, and it will just make the level of your automation a lot higher.

I thought of another question here, because I know some some end customers are like: "Oh, should I have a weather station or not, do I need it or not?" So, do you think if somebody is not sure if they should put in a weather station, what do you think an integrator should do? Because I'm thinking there's probably an easy way to do some kind of pre-installation, and, you know, see, like after one year that you need it or not. What do you think about that?

Yes, it's also an interesting question. So in my experience, when discussing with end customers it's sometimes good not to go from the material or product perspective - more go from the functionality perspective...

The use cases right?

Exactly! Ask your end customer. If you're a system integrator, ask your customer: "How important is automated shading to you?" if he says: "Yes", then you should definitely recommend the weather station. Tell him: "Okay, if you want to have this functionality go for a weather station" if he says "No, I don't have any engines in my blinds, so I don't want to have it automated, it's simply not important for me." Then you don't need the weather station, it's really simple. But don't start discussing a weather station, and explain what the weather station can do. Better go from the other side, and ask: "What functionality is important to you, what do you want to achieve with your home automation?"

Well, thanks for this answer, and actually that's basically it from my side. So, is there something you want to add at the end of our session?

No, it's all good from my end. I also want to thank you for the opportunity to be a guest in your podcast. It was a great fun, and pleasure talking to you, and yeah, I'd say until next time!

Yeah, definitely! Thanks for sharing your wisdom. What about you, our viewers? Let us know what your opinion is about the weather stations and you can do that by partaking in our survey, by clicking the link below. And you know, welcome to subscribe to our channel, post, share, comment, you know, the usual, and see you in the next episode of Talking Smart Homes.

And yeah, Auf Wiedersehen!