KfW 55 - Ventilation system yes/no? - Experiences

Thank you for your answers.

, I think I may have expressed myself somewhat unclearly. According to calculations, the house already meets the KfW-55 standard. =) I will inquire about it tomorrow.

, it is primarily about the ventilation system... It is definitely interesting to have heard your friends' assessment.

The fact is, however, that the whole thread is clearly in favor of the ventilation system.

, it is primarily about the ventilation system... It is definitely interesting to have heard your friends' assessment.

That is why I would have preferred to call the general contractor today rather than tomorrow or to have appeared in person.

The fact is, however, that the whole thread is clearly pro ventilation system.

Definitely. The forum is such a great help and I am grateful for many threads and personal assistance.

After all the posts, I feel like I'm suffocating in the KFW55 house without controlled residential ventilation. :-D

I have that feeling in almost every energy saving ordinance house, but many don't know any different and think it has to be that way.

It is comfort. Nothing more and nothing less. Similar to seat and steering wheel heating in a car.

I am another voice in favor of controlled residential ventilation. We have been living in our KFW55 new build with a central ventilation system for half a year. We initially had it calculated individually – the price might not necessarily be useful to you, as a decentralized ventilation system was already standard for us. The surcharge for the central one would have been between 5-6k €. In the end, we built with a combination unit (air-water heat pump, controlled residential ventilation, and hot water in a huge box). I have never had such good air, we love the controlled residential ventilation.

So, I looked again. With the [GÜ] (or rather his HSL sub, who gave up because of my detailed questions about heating and ventilation) the additional cost would have been about 20,000 EUR (gross) (but also because I needed an extra floor in the upper floor to install the pipes for the ground floor ventilation in the floor structure, which costs about 1900 EUR). I then found my own HSL specialist and the share for the controlled residential ventilation is about 8400 EUR (gross) plus the extra floor and additional insulation (about 500 EUR) and possibly one or two core drillings. So in total just under 12,000 EUR. The system itself is a Vaillant RecovAir 260. The house has 162m² of space. I estimate that an additional cost of 10-15,000 EUR through a general contractor would still be usual for you. Beyond that, he basically doesn’t want to do something like this.