ᐅ Design and Planning of Controlled Residential Ventilation Systems – Experiences

Good morning dear forum,

I received today the planning documents from the prefab house manufacturer regarding the mechanical ventilation with heat recovery. Please see the attached images. The plan itself was created by an external company, not the house builder.

However, since several things have already gone wrong with the builder, I have some concerns with such a sensitive topic as the design of the mechanical ventilation system, and I would like to ask for your advice here to be sure that no shortcuts are being taken. As you can read here, even the smallest details can play a big role, for example when it comes to noise levels.

According to the legend, the plan is for a Zehnder mechanical ventilation system, which is already a concern because our ventilation unit will be a Viessmann Vitovent 300-W H32S C400 with a maximum airflow of 400 m³/h (235 cfm).

Also, the Ø130 mm (5 inches) diameter mentioned in the legend makes me think. If I understand the installation manual of the Viessmann mechanical ventilation correctly, larger duct diameters would be necessary for our system, which also raises my worries about noise.

What do you think about the placement of the vents? We definitely want to adjust some locations, as for example the supply vent in the bedroom on the upper floor is exactly at head height where our bed will be. Also, I’m not sure if the exhaust vent in the upper floor hallway is a good idea there — might we be pulling cooking smells up even more through the air space? In the living room on the ground floor, the outlet is exactly at foot level next to our L-shaped sofa; could that be uncomfortable in winter? Shouldn’t the exhaust in the kitchen be closer to the cooking area? In the basement and ground floor, the vents come out of the ceiling, and on the upper floor from the walls, presumably avoiding exterior walls.

I’m absolutely not an expert, just someone who likes to read up on things, so it might all be okay. But as I said, quite a few things have already gone wrong due to carelessness, and I am not sure if the planner was even properly informed about the exact mechanical ventilation unit, especially since there are three variants of the Vitovent 300-W with different maximum airflow rates.

Could you help me a bit or even ease my fear of mistakes?

We are very grateful for your help, for sure!

Best regards
Paul

The kitchen can be a bit closer to the cooktop, but in my opinion, it’s not necessary.
We don’t have any exhaust ventilation in the hallway on the upper floor. However, I don’t think odors upstairs should be a problem. Most of it will be removed downstairs through the range hood and exhaust system.
I would omit the air outlet near the sofa, especially if you are sensitive to drafts.

I can’t say much about the rest. We didn’t really take care of the ventilation.

baueninbw schrieb:

Today I received the design for the mechanical ventilation with heat recovery from the prefabricated house manufacturer. See the pictures attached. The design was prepared by an external company, not the house builder.

Since quite a few things have already gone wrong with the house builder, I have some concerns about such a sensitive topic as the design of the mechanical ventilation system. I would like to ask for your advice here, just to be sure that no corners are being cut in the wrong places.

I find it surprising that, on one hand, "quite a few things have already gone wrong with the house builder," yet nothing of this is apparent in your thread history. So you have received a design proposal — but from whom exactly? I assume it is from a subcontractor of the house builder (?), definitely not from the problematic party themselves, so initially there should be no reason to doubt the planning expertise behind it. Or is the subject of your question precisely whether the system has been assembled from the right components and whether the recommended manufacturers were correctly chosen?

If I am not the only one unclear about this so far, it might explain why there are unexpectedly few members stepping in to help.

If you have been following the forum for some time, you have probably noticed the members who are experts in this area (for example, I am visibly not a specialist in heating, ventilation, and air conditioning). Address these members directly by putting an @ before their username (like @baueninbw) to catch their attention in your thread, as they usually do not browse the forum very frequently.

It would also help if you could share not only the plans but also your expectations and views regarding the mechanical ventilation system. At the moment, we can hardly tell anything. Naming the house builder and describing the wall construction could also be illuminating. For example, why does the basement (which seems to be purchased from somewhere) recess by a full 24cm (10 inches) behind the ground floor? Where is the gas and water connection (GOK), and so on?

A provided colorful legend alone does not compensate for the almost complete lack of background information!

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https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

@11ant
Please don’t take this the wrong way, but in my opinion, the points you raised are not related to the actual questions I asked. I believe my questions were clearly stated, and any side issues don’t help to solve the problem.

If there were forum members here who could assist me, a fruitful discussion would naturally develop on its own.
This is just my opinion and definitely not intended as an attack, honestly. Thank you for your response, either way.

The house will arrive in about 6 weeks, the basement in 3. I don't have much time left, which is why I’m in a hurry... I understand that not everything can be completed in two days, but the builder simply took so long to send me these things, maybe even intentionally delaying it...

baueninbw schrieb:

According to the legend, the plan is for a Zehnder controlled residential ventilation system, which is where it already starts, because our ventilation system will be a Viessmann Vitovent 300-W H32S C400 with a maximum air volume flow of 400m³/h (235 CFM).

This is not something to worry about. A planner usually does not buy software from every manufacturer multiple times, since the calculations are basically the same.
What matters is that the calculated total volume flow and the resulting air change rate fit the total volume of the house. 400m³/h (235 CFM) sounds reasonable for three floors.
Is the basement also used as living space?

baueninbw schrieb:

Also, the diameter listed in the legend of Ø130mm (5 inches)

That doesn’t sound critical at first. Noise development depends on both diameter and air volume flow. I’m not experienced enough to say whether it really will be silent; I think even an expert would need to see the full calculation, not just the installation suggestion.
Of course, having multiple or larger outlets does not harm noise levels, but you have to pay for that, of course.

baueninbw schrieb:

What do you think about the placement of the valves? We definitely want to adjust something, since, for example, the outlet in the bedroom on the upper floor is exactly at head height above our bed.

Yes, having an outlet directly above the head is not ideal—it causes a noticeable draft.

baueninbw schrieb:

Could this cause cooking odors to rise even more through the airspace?

baueninbw schrieb:

Should the exhaust in the kitchen be closer to the stovetop?

I don’t think so, since there is an extractor hood directly in the kitchen area. However, you should let go of the idea that the controlled ventilation system will strongly remove odors—regardless of whether it’s directly above the stove or not.
For that, you would already need an extremely effective extractor hood, which, by the way, is not designed to prevent odor spread throughout the home but to capture cooking fumes directly.

baueninbw schrieb:

In the living room on the ground floor, the outlet is exactly at foot height of our L-shaped sofa. Could that be uncomfortable in winter?

If you are very sensitive to drafts, yes. It also depends on whether you plan to sit barefoot on the sofa in winter and, of course, how draft-sensitive you are. As mentioned, on normal settings, it is noticeable. We actually have an outlet directly above the sofa, and it is noticeable but not so unpleasant that it keeps you from sitting there. I sometimes even find it comfortable.

baueninbw schrieb:

In the basement and ground floor, the valves come from the ceiling with this builder, and on the upper floor from the walls, presumably exterior walls are avoided.

Yes, that’s fairly standard. Where exactly do you see a problem here?