Atypically high offer for ventilation system

Youtube > Ventilation system - Do you need it? Energy consultant explains

In 2015, I had an apartment building with 6 units built according to KfW55 standards. This building has been rented out since early 2016, so for almost 8 years. Since the beginning of the rental period, there have been many tenant changes; in each apartment, there is now at least a second tenant. After many discussions with experts and ultimately for cost reasons, I decided against installing a ventilation system. The cost of a ventilation system would have had to be passed on in the price per square meter. In other words, renting at a slightly lower price per square meter was and is more economical for me. The primary concern I had was the issue of mold growth. In the 8 years since renting, I have never had any problems with mold in any of the apartments. I agree that a ventilation system significantly increases comfort, but my example shows that it is possible without one. I do not believe that I have been lucky enough to rent to the best tenants from all over Germany.

I am not saying that maintenance is necessary, the manufacturers say that. The manufacturers also deny warranty and guarantee if you perform the maintenance yourself. Of course, you can save money with your own effort. But that is not the standard case.

I see one of the main reasons we are so absurdly backward with ventilation systems in residential construction here in the landlord-tenant relationship: the landlord understandably only looks at their construction costs. The tenant has so far also completely ignored the additional costs. Heating gets a bit more expensive? Only the tenant notices. Damp corners or moldy silicone seals? Only the tenant notices and doesn’t dare to say anything because if they say something, they (also understandably) get a scolding from the landlord to "ventilate properly." This is ignored to death and at best treated with one of the mold removers sold in large quantities for good reasons. Condensation water runs down the windows in streams? No problem, to combat this, an acquaintance is currently installing triple-glazed windows throughout the whole house.

So yes, as a landlord you only have problems with mold when it is far too late. Not because there was no mold before, but simply because it cannot be seen. That’s the perspective of a landlord over a few decades.

The fact is: the only thing that can speak against a controlled residential ventilation system at all is the initial investment. And when I think about some of those "I took the model house and made everything 20% bigger" and "I can’t live without a double garage and lemon-squeezer roof and fully glazed south wall" house designs, and then the "well, a kitchen with a granite cooking island and steam cooker just costs 30k" and the SUV with extras worth just as much parked in the driveway, I really wonder how many different standards are being applied here. In Cologne they say "kitchen laminate, brocade in the living room" and the whole infrastructure is built as cheaply as possible. Heating? Water? Electricity? As cheap as possible. As if we didn’t already have enough unsalvageable buildings with the paper-thin prefabricated buildings, we happily continue to erect buildings in the landscape where the core was economized on.

I would have said, just have the pipes laid and then connect the device yourself. Or is that what you mean?

Simply up to the octopus and then buy the device yourself, connect it and commission it. Such a device is as complex as a toaster.

or do everything yourself. From the air distributor onwards we laid everything ourselves and connected valves etc. The rest was done by the plumber. But you’re right, controlled residential ventilation is easy. Next house I’ll do everything myself ;). Like with the wall heating, I had it done, next time myself (P.S. There’s probably no next time, I’m 56 and originally wanted to stay there until I emigrate)

Yes, retrospectively I also find the system alarmingly simple. The ventilation system is also what I have already changed the most. A pipe is a pipe is a pipe and no water can leak out of these. In the utility room, I optimized the supply air so that the photovoltaic system and server cabinet are better supplied, confirmed by measurements. I also found the installation of the lines very pleasant. Where you should not save is in the design of the system. Acquaintances used one based on the manufacturer's calculation tool, which was too small from experience and now runs constantly at full load. You should also not save on the silencers.