KfW 70 without ventilation system

Hi,

can you still find a builder today who admits to having built without [Kontrollierte-Wohnraumlüftung]?

Whether and how it works is now almost secondary, the main thing is that I have my single-family house with [Kontrollierte-Wohnraumlüftung].

However, there are certainly planners who, after considering all the details, hold a different opinion. There are also builders who do not miss the absence of [Kontrollierte-Wohnraumlüftung].

best regards fm

Hello €uro,

Modern buildings are relatively airtight, which is both sensible and necessary. However, a simple window ventilation is still sometimes completely sufficient for normal buildings (Energy Saving Ordinance, KfW 70), even if the business with fear of mold is booming.

I really don't know whether I should laugh or rather get annoyed

Apart from the fact that the first part of the above sentence is already an irresponsible stupidity in itself – less airtight houses would cause fewer problems and less and ever more expensive technology – the second part shows absolute naivety. Today's houses are so airtight that "normal" window ventilation often no longer suffices; especially in times when open spaces or higher ceiling heights are very popular _and_ also precisely when both partners are employed. This heat/humidity buildup becomes particularly charming where a non-openable window has been installed in the open space.

Knowing – that there are also quite a few bad apples among house sellers – I resist being placed under "general suspicion" with the implied suggestion that there is also a commission for the ventilation system. People affected by moisture problems will be happy, because you surely stand ready with compensation for your statement "However, a simple window ventilation is still completely sufficient for normal buildings (Energy Saving Ordinance, KfW 70)" to anyone affected?

As for controlled ventilation _with_ heat recovery, no technician has yet convinced me in "normal" house construction (< KFW 55), but anyone who, like me, has experienced a 0.7 or below as a result of the blower door test reacts very sensitively to the blanket statement that in the KfW 70 efficiency house the business with fear of mold is elevated to a mantra.

Kind regards

The houses built today according to the latest state of the art and the requirements of the Renewable Energy Heat Act as well as the Energy Saving Ordinance are so tightly sealed that normal ventilation is usually not sufficient to get the moisture out of the house. Keep in mind – especially if you and your husband both work – when you can ventilate?

I generally consider a ventilation system to be a good thing, but I think the idea that the moisture cannot be removed from the house because one is employed is incorrect. If you ventilate well once in the morning before work, the moisture is already out. If no one is in the house during the day, no moisture should form (unless the apartment is full of plants).
Regards

Hello everyone,

we also have a controlled residential ventilation system (Pluggit) in our new build (prefabricated house KFW 70)!!!
I have to say that we don't want to miss it anymore.
There is nothing nicer than waking up in the morning in the bedroom and having fresh air in the room/the whole house, and why shouldn't you continue to use the energy you acquire in the house (bathroom/kitchen) at a high cost.
At first, we were also a bit skeptical about whether we should do it, since we couldn't imagine never having to open windows again, can that be true? But it is indeed such a great indoor climate throughout the whole house for little money (electricity cost per year 96 euros)

Regards

Hello,

...I really don’t know whether I should laugh or be rather annoyed

Just choose what fits.

... This heat/moisture accumulation becomes especially charming where a non-opening window has been installed in the airspace.

Who makes/plans such nonsense? First create a moisture/heat accumulation and then persuade/convince the builder to install a controlled residential ventilation system to solve the problem. Well, there really isn’t much competence here.

implicit hint that there is a commission for the ventilation system anyway.

Ah, yes – I forgot, everything is just gifts and completely selfless.

Those affected by moisture problems will be pleased,.....

There are no moisture problems if the necessities/requirements have been properly clarified. Apparently, you don’t manage that and therefore prefer to sell a controlled residential ventilation system additionally.

...No technician has ever convinced me of controlled supply and exhaust ventilation _with_ heat recovery in "normal" house construction (< KfW 55), ....

No one has to be convinced here. You only need to be able to understand/comprehend. If you can’t manage that, then just leave out the heat recovery for your customers.

Best regards

Hello €uro,

don’t worry about my competence, I can look in the mirror every morning with a clear conscience.

I am definitely capable of creating a heating demand calculation and, in this context, also a cost/benefit analysis. Especially regarding the latter, heat recovery in a single-family house KfW 70 is not a game changer – measured against the saved energy in relation to the increased investment costs. So your sarcasm misses the mark, especially since I do not fail to inform every potential builder about the advantages and disadvantages as well as cost-effective alternatives, involving trade-specific experts in the discussions. If they btw. decide on the latter option, the compensation for the service I provided also ends. However, you probably will not understand my motivation behind this; based on the training underlying you, probably too much to expect.

Kind regards