ᐅ Wall or roof penetrations (external / fresh air intake) – how have you installed them?
Created on: 27 May 2016 07:53
B
bortel
Hello everyone,
Since I now have to decide which wall or roof penetrations we need to use for the fresh air intake and exhaust air, I am looking into the various options available on the market.
On the north side, we have the possibility to take in fresh air through the gable. The north gable faces the street, so the solution should also look decent.
The idea is to route the exhaust air through the roof, but the south gable can also be used for exhaust air. The south gable faces the garden.
We are building a house on a slope, which means that from the street side you see one full story and the pitched roof with the attic and loft. The heat recovery ventilation unit will be installed in the loft.
So far, I haven’t found a fresh air intake and exhaust air solution that really convinces me.
What have you installed, and what makes sense?
We have a planner for the heat recovery ventilation system, but I want to take a broader look at what is available.
Regards,
Micha
Since I now have to decide which wall or roof penetrations we need to use for the fresh air intake and exhaust air, I am looking into the various options available on the market.
On the north side, we have the possibility to take in fresh air through the gable. The north gable faces the street, so the solution should also look decent.
The idea is to route the exhaust air through the roof, but the south gable can also be used for exhaust air. The south gable faces the garden.
We are building a house on a slope, which means that from the street side you see one full story and the pitched roof with the attic and loft. The heat recovery ventilation unit will be installed in the loft.
So far, I haven’t found a fresh air intake and exhaust air solution that really convinces me.
What have you installed, and what makes sense?
We have a planner for the heat recovery ventilation system, but I want to take a broader look at what is available.
Regards,
Micha
Do you know if this has ever been studied anywhere, or do you have any sources to support your statements? Regarding the combined supply and exhaust air at the exterior wall, I found the flow diagram by Vallox convincing. For the vents above the door, the arguments often refer to long-throw vents and the Coanda effect. However, I am not an expert in fluid dynamics and am happy to be corrected...
S
Sebastian792 Jun 2016 08:08I can only refer to my discussions with an engineer specializing in such ventilation systems, the plans from my supplier, and the design guides from Helios/Zehnder – these are fairly straightforward principles.
The Coanda effect is also explained there, but it is not considered a reason to allow valves above doors.
I am definitely not an expert. I just don’t trust individual claims from companies that pull such “miracle solutions” out of thin air, especially when the rest of the system is still designed conventionally with two offset air inlets and outlets.
The Coanda effect is also explained there, but it is not considered a reason to allow valves above doors.
I am definitely not an expert. I just don’t trust individual claims from companies that pull such “miracle solutions” out of thin air, especially when the rest of the system is still designed conventionally with two offset air inlets and outlets.
Yes, I have also seen that only one Vallox unit is needed. That’s why the ventilation specialist was quite skeptical, especially concerning the cross-sectional areas. I am now going with the thermal bridge-free model from Westaflex. Fresh air inlet on the north side and exhaust air outlet on the south side; this way, I won’t need any additional roof penetrations.
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Sebastian792 Jun 2016 09:02I will take photos for you this evening.
Robbaut schrieb:
That is incorrect; you only need one. The Vallox weather protection grille is designed for both supply and exhaust air, so you could install it on the south side and wouldn’t need a grille on the north side.
It has been working perfectly for us so far.That is not incorrect.
The intended use as both supply and exhaust air grille requires that:
- the system is planned that way from the start
- the two ducts run side by side in the wall
- the ventilation installer is familiar with the system
- the ventilation installer cooperates.
There are simply too many “ifs” to answer the simple question about one ventilation grille. That is why I recommend installing two.
It’s great that the grille works well for you. However, your system was specifically designed for that.
Most ventilation installers are not familiar with that grille, and convincing them otherwise is a challenge. In many cases, they simply refuse to provide any warranty.
Sebastian79 schrieb:
I can only refer to my discussions with an engineer specialized in such ventilation systems, the planning by my supplier, and the planning resources from Helios/Zehnder – these are fairly simple principles.
The Coanda effect is mentioned there as well, but it is not considered a reason to allow vents above the doors.
I am certainly no expert either. I just don’t trust isolated statements from companies that then present such "miracle solutions," while the rest still plan conventionally with two offset supply and exhaust openings.Our Helios system, designed by Helios, also only has a combined façade grille.
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