Controlled residential ventilation makes sense for us or is even necessary.

Hello everyone,

we will soon be building in the Bremen region. Planned are 130 sqm, double-shell masonry, 45° gable roof, with gas boiler, underfloor heating, orientation S/W, flat collectors for domestic hot water preheating with storage, Kfw 70(+) without any further frills. Those are the key data.

We often deal with the question of whether to have controlled residential ventilation or not. We have been offered the ready-to-install recoVAIR 275 for 9.3K €. We are currently (still) two people and both employed. In addition, we are often away on weekends, so at least two weekends a month from Friday afternoon to Sunday afternoon no ventilation can take place.

How do you see that?

Best regards Heiko

Hello Heiko,

a [Kontrollierte-Wohnraumlüftung] is, in my opinion, a comfort feature. It may not always be necessary, but all my acquaintances who have such a system in their houses would no longer build without it...

Of course, you can also ventilate properly manually, but especially with your usage profile, a [Kontrollierte-Wohnraumlüftung] would be a sensible thing, I think.

Regards,

Dirk

....We are currently (still) two people and both employed. In addition, we are often away on weekends, so that at least two weekends a month from Friday noon to Sunday afternoon cannot be ventilated.....

On the one hand, where should odors, moisture come from if no one is present? On the other hand, the "critical rooms" are mainly bedrooms, bathrooms and kitchens. Bedrooms: Modern buildings are intentionally built to be almost airtight according to requirements. For example, if the window faces a busy main road, an open or tilted window is hardly suitable. These are the rooms with the longest usage/load time! Here, odors, CO2 load play the biggest role. The ventilation stage setting alone of DF is usually not sufficient. Rain and snow situations also usually prevent partial additional opening. In a "dance hall," two people can sleep over without the CO2 concentration noticeably changing due to the room volume. With 30 m³ room volume, it looks completely different! Bathrooms: Rooms with low usage time but high moisture load. In windowless rooms, at least exhaust ventilation is usually required according to the state building code. However, the supply air must also come from somewhere. Whether window ventilation can be sufficient also depends here on the room volume and the load. The same limitations apply if only DF are present! Kitchens: Here, odors and moisture are essential. For someone who cooks daily or constantly, the conditions are completely different than for occasional weekend cooking! "Steam kitchens" are certainly the exception in single-family houses. In terms of room volume, small, closed, intensively used kitchens require a completely different air exchange than sparsely used, open kitchens with large room volume. Sometimes, overall decentralized partial solutions can be effective despite lower efficiency individually. However, I consider equipping an entire building with decentralized controlled residential ventilation largely unrealistic. Even a central controlled residential ventilation can go significantly wrong; whether one should spend ~10,000 € on this, I would not think so. As always, the building-specific needs/requirements are decisive, which makes a reliable, general recommendation impossible in advance! Best regards.

Hi,

thanks for your answers. The topic of comfort certainly plays a role in controlled residential ventilation. Of course, I try to approach the topic quite objectively from a cost perspective. The explanations from €uro are very helpful in this regard. I hadn’t considered a partially decentralized solution yet. Although all rooms (except hallways and utility rooms) will have at least one window. Maybe a note on the topic of olf. We are building directly opposite a farm with a cowshed. Ventilation will always be an olfactory experience there. Perhaps just for that reason alone, a controlled residential ventilation system. We actually cook fresh food almost every day, but without a steam cooker. Therefore, we plan to install a powerful exhaust system for the kitchen, even with controlled residential ventilation.

Honestly, I hardly trust a "normal" general contractor to provide sound advice on the topic of controlled residential ventilation. Who should I best turn to? Independent building consultants, energy consultants, architects?

Best regards and have a nice weekend
Heiko

... We are building directly opposite a farm with a cowshed. Ventilation then also always becomes an olfactory experience. perhaps for that reason alone a controlled residential ventilation system.

Correct, such construction project specific peculiarities can have a significant influence on finding a sensible solution.

... I honestly hardly trust a "normal" general contractor to provide sound advice on controlled residential ventilation...

The assessment is certainly appropriate, since general contractors are more interested in sales than the actual well-being of the builder. On the other hand, as market participants, this cannot be held against them.
Everyone wants to have their share of the available cake. For this purpose, almost all means are justified, as long as the builder (client) allows it.

... Who should I best turn to? Independent building consultants, energy consultants, architects?..

Most likely to an independent MEP planner who specializes in small units such as single-family homes. They are needed anyway for heating and hot water.
Large MEP offices are rather unsuitable for this (cost, expertise).

Best regards.

Hi,
many thanks €uro for the assessments and suggestions. I have now contacted a TGA specialist planner. He specializes in small units (mostly passive and EnergyPlus) and can take over the entire planning for the single-family house. I am curious to see what will come out in the end.
Thanks & regards
Heiko