New building as a KfW-55 house with which ventilation system?

My experience with ventilation systems:

There is no good or bad one... every reputable manufacturer offers more or less the same... ultimately, it is a matter of price and additional features, such as remote control, enthalpy, bus connection etc., different numbers of pre-programmed ventilation levels, and so on.

What you need from that you have to decide yourself... they all ventilate equally well...

In the course of selecting the system for our house... I had contact with builders and visited houses with various systems, including Pluggit, Helios, Zehnder, Vallox, Wolf, etc.

Both central and decentralized solutions.

The core of every central system (apart from the heat exchanger) are the two fans and their control; here, however, there is little difference to notice... regardless of the manufacturer... one blows in, the other blows out... the noise level is comparable... the difference between the systems lies in the additional functions... to put it mildly, the same "thing" is inside everywhere, whether Pluggit, Helios, Zehnder, Vallox, Wolf...

Hello Cathy

We built a house of similar size and design three years ago.

Ventilation system Paul Thermos 300DC with constant volume flow control (due to a room air-independent stove) and fresh air intake via ground heat exchanger (30m pipe DN200 in the ground).
Additionally, we also heat through the ventilation system; for this, a hot water heating coil is installed in the supply air.

We are very satisfied with the device; it runs without faults. Due to the counterflow heat exchanger, it has a high efficiency. Together with the ground heat exchanger, the efficiency is at least so high that the device usually shows no difference in temperature between supply air and exhaust air.

The basement is part of the insulated envelope and has corresponding perimeter insulation. The basement is also ventilated and partially heated (office). Where it is not heated, I have currently turned off the ventilation valves.
The basement room with the solar tank is also our laundry drying room, accordingly there is a supply air valve here.
I consider it sensible to ventilate the basement if it is partially used for living purposes. The few pipes and valves do not cost much, and retrofitting later will be rather difficult.

I can warmly recommend a pocket filter in every exhaust air valve. These get clogged after one year. With this measure, you also protect the more expensive main filter in the device. The pocket filters can be made very cheaply from an EU4 filter mat.

Personally, I don’t think much of all the manual measuring in. The professional knows – who measures, measures rubbish! The valves clog over time, and the once determined values no longer apply anyway.
In my case, the constant volume flow control ensures that the balance between incoming and outgoing air always matches.

Good luck!
Bernd