Atypically high offer for ventilation system

This is a classic cost comparison calculation for evaluating an investment. But if you think you can completely ignore business administration, then we don't need to discuss this any further here. This disqualifies you by itself.

Is an owner-occupied house an investment? That would be a prerequisite for considering it as an investment calculation. If we open that can of worms, much more would have to be examined. Starting from the location (here in the village it is nice, but certainly not the ideal investment location) to the tile. For every detail of the equipment, you have to ask whether you either save costs or sustainably increase the value. Money invested in the house must then be discounted with an appropriate return, for this you have to include a fictitious comparative rent. If you do that, a house will rarely pay off as an investment.

But one thing I noticed: There are hardly any reports from opponents who have already had one. Actually only experiences from people who don’t want to miss having one anymore afterwards.

Of course it is easier to be against something you only know by hearsay ;)

Imagine you are explaining to a person who only knows oil single stoves and wood-burning stoves the advantages of underfloor heating and an induction stove. One can respond with a "hmm, interesting, maybe I'll try it sometime" or with a crude mix of blanket rejection and fabricated counter"arguments". A nice example is the transition from the ice box (that is, the wooden box in which "harvested" natural ice was stored for cooling) to the refrigerator (that is, the compressor refrigerator we know): Back then, ice box manufacturers seriously put forward the counter"argument" that refrigerators were incredibly unhygienic because they were not cleaned by the constantly running meltwater from the ice block (in which there was often highly unpleasant bycatch, since it was harvested natural ice, not industrial ice).

How many of you still have an ice box at home today?

Oh damn, you mean I should have harvested the snow that all the rain has now washed away? Argh wasted opportunity.

Well, I doubt that a controlled residential ventilation system in a privately used single-family house will ever be economically viable (you also have to remember maintenance, wear and tear, and consumables). But you can always "bend" the calculation one way or the other.

I'm not even saying that it wouldn't be possible without it.

In any case, I say that I wouldn't want to do without it and if I ever build a new house, I will plan with it again. For existing buildings, I would somehow try to retrofit it. Not at any price, but then if necessary with my own work, before I leave it out entirely.

We have a controlled residential ventilation system in our new building and one thing I didn't consider before is the dry air in winter, which is not beneficial for the parquet flooring (which we have almost everywhere). Otherwise, I enjoy not having to think about opening a window at all.

My energy consultant calculated my energy consumption with and without [Kontrollierte-Wohnraumlüftung]. In the end, a [Kontrollierte-Wohnraumlüftung] is usually not economically worthwhile. For 144 sqm of living space, my savings amount to just €430 annually minus €43 electricity consumption for the [Kontrollierte-Wohnraumlüftung]. So, only about €387 per year. Because I installed the system myself, my costs amounted to only about €6200. Nevertheless, I did not want to be without the system anymore. The comfort gain is quite remarkable. Not only fresh air but also actually less dust in the apartment. The fact that there are no more flies in the apartment is, of course, also not bad.

Maybe heating energy finally needs to be priced in a way that holds people accountable for the consequences of their actions. Then it will pay off faster. Until then, it is "only" about avoiding completely unnecessary heated air being aired out. It's called environmental protection. You can do it even if it doesn't pay off within ten years.