ᐅ Best Smart Home Upgrade for New Construction

@daniel0319 What @hanse987 is saying is exactly the key point. Air always moves toward the coldest spot. So, the warm air from the heated rooms will warm the cooler rooms. Naturally, this means that the heating system in the rooms where you want higher temperatures has to work against this and becomes less efficient. If you add a controlled mechanical ventilation system, which is common in KfW55 standard homes, regardless of the standard but generally recommended, this effect is even stronger.

The solution for you would likely be to adjust the hydraulic balancing so that the overall lower temperatures you want are reached, and then use additional local heat sources in the rooms where you want it warmer, such as infrared radiators, when needed—like when showering or for other activities.

Anything else will just result in the temperatures evening out across the whole house.

Edit: You should not focus on the 22–23°C (72–73°F) I mentioned. Those were the temperatures we told the heating engineer, on which the heating system was designed accordingly. You tell them you want 20°C (68°F) or whatever temperature you prefer, and they design the heating system based on that. Whether it’s 20, 22, or 30°C (68, 72, or 86°F), the principle is the same.

If I increase the heating by just 0.5°C (0.9°F), we only notice it after 24 hours. For individual rooms, this will never work in a modern house.

daniel0319 schrieb:

What about lighting and blinds? I was thinking of using actuators like Shelly or Sonoff behind the switches (we are installing deep electrical boxes throughout the house).

That can work. However, you would then be 100% dependent on a stable Wi-Fi connection in every corner of your house.

daniel0319 schrieb:

By the way – ventilation system – does it make sense to make that smart?

All this “smart” stuff… just because something can be controlled via an app doesn’t mean it’s truly smart or smartly implemented. Ventilation usually regulates itself automatically. You might consider programming a party mode into the control system’s interface, but even with increased occupancy, the system will eventually adjust on its own.

untergasse43 schrieb:

That’s one way to do it. You’d then be 100% dependent on a working Wi-Fi signal in every corner of your house.

All this “smart” stuff… just because something can be controlled via an app doesn’t automatically make it smart or well-designed. Ventilation usually regulates itself. You might consider programming a party mode in the control interface, but even increased occupancy is eventually detected by the system itself.

There is an access point installed exactly in the middle of the house on each floor. Ideally, I would like to control everything via Zigbee. I have a friend who uses many Shelly devices and has experienced some issues (very slow web interface) with his FritzBox 7390 (probably due to the large number of Wi-Fi devices). But a FritzBox should actually be able to handle that. So I’m still undecided.

Could anyone recommend reliable Zigbee actuators for light switches and roller shutter switches?

I understand that “smart” doesn’t just mean “app-controlled”; I was just asking to gather suggestions or ideas.

Patricck schrieb:

In most cases, building projects also include radiators with valves. I don’t know of a single construction site without room thermostats or valves, slow response or not. It doesn’t matter whether it’s residential buildings or single-family houses.

When building with KfW standards, individual room control is even mandatory, as far as I know.

Just to mention: we have neither EER nor control valves (the plumber performed a hydraulic balancing). We built with a general contractor (KfW55) and decided to install this ourselves later (I was considering Homematic IP wireless room thermostats). Currently, we don’t use any EER. Neither the commissioned electrician nor the general contractor showed much interest.

edit: Homematic IP can also be well integrated into HomeAssistant
edit2: There is also a suitable interface for the ventilation system – in my case a Vaillant RecoVair. I have everything in HomeAssistant and can set up my automation there.

untergasse43 schrieb:

Ventilation usually adjusts itself automatically. One could consider programming a party mode into the visualization, but the system will eventually notice an increased number of occupants by itself.

Is that really the case? I understand the principle when it comes to demand-controlled ventilation (DCV), and it definitely makes sense.
However, I’m currently unsure whether this also applies to mechanical ventilation with heat recovery. Do they really self-regulate?
Don’t mechanical ventilation systems typically have just 3 or 4 fixed speed settings, each providing a constant airflow?
In theory, it could work like underfloor heating: measuring relative humidity, temperature, and CO2 levels at the outlet, and then adjusting the overall airflow accordingly. But is this actually done? And would it even work, or are the sensors not accurate enough to detect fluctuations when measuring overall values rather than on a room-by-room basis?

I’m not an expert on this topic, these are just thoughts based on assumptions rather than real knowledge.
I’d appreciate any clarification on how this works in practice.

The only function that the recoVair from Vaillant controls is the ventilation rate based on a time schedule with two patterns for day and night. You can also add an offset if a certain humidity or CO2 level is exceeded, but this applies to the set ventilation level—at least with the recoVair.