ᐅ Controlled Residential Ventilation System – Decision Guide
Created on: 22 Oct 2017 11:14
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baumhaus815
Hello everyone,
We have decided to build with GÜ, and construction is about to start soon. Now we need to choose a specific mechanical ventilation with heat recovery system.
The single-family house has three floors (basement, ground floor, upper floor), and the floor area of each level is about 80 sqm (860 sq ft). The mechanical ventilation system is planned only for the ground and upper floors, not for the basement.
We are currently choosing between two systems: the Zehnder Comfoair Q350 and the Wolf CWL-300. The Wolf system would be 1,700 euros cheaper overall (including ductwork, installation, etc.).
From what I understand, the Comfoair Q350 is the newer system, has lower noise levels, and a higher heat recovery efficiency. Additionally, it is dimensioned for 50 m3 (1,765 cu ft) more airflow than the CWL-300, which might mean it could run at a lower fan setting during normal operation, making it quieter and more economical.
Our considerations now are: Do the lower measured noise levels actually make a noticeable difference in everyday use (or only under laboratory conditions)? Regarding the system sizing: In theory, 300 m3 (10,595 cu ft) max capacity would be sufficient for us, but would 350 m3 (12,366 cu ft) be better in practice? Ultimately, the Comfoair Q350 is probably the better system, but we wonder if the additional 1,700 euro cost is worth it for our house.
Which mechanical ventilation with heat recovery system would you recommend as experts? As non-professionals, it’s quite difficult for us to make the right choice.
Thanks in advance!
We have decided to build with GÜ, and construction is about to start soon. Now we need to choose a specific mechanical ventilation with heat recovery system.
The single-family house has three floors (basement, ground floor, upper floor), and the floor area of each level is about 80 sqm (860 sq ft). The mechanical ventilation system is planned only for the ground and upper floors, not for the basement.
We are currently choosing between two systems: the Zehnder Comfoair Q350 and the Wolf CWL-300. The Wolf system would be 1,700 euros cheaper overall (including ductwork, installation, etc.).
From what I understand, the Comfoair Q350 is the newer system, has lower noise levels, and a higher heat recovery efficiency. Additionally, it is dimensioned for 50 m3 (1,765 cu ft) more airflow than the CWL-300, which might mean it could run at a lower fan setting during normal operation, making it quieter and more economical.
Our considerations now are: Do the lower measured noise levels actually make a noticeable difference in everyday use (or only under laboratory conditions)? Regarding the system sizing: In theory, 300 m3 (10,595 cu ft) max capacity would be sufficient for us, but would 350 m3 (12,366 cu ft) be better in practice? Ultimately, the Comfoair Q350 is probably the better system, but we wonder if the additional 1,700 euro cost is worth it for our house.
Which mechanical ventilation with heat recovery system would you recommend as experts? As non-professionals, it’s quite difficult for us to make the right choice.
Thanks in advance!
B
Bieber081524 Oct 2017 18:12The crucial factor is the planned airflow per outlet (i.e., m³/h per outlet). With this information, you can then consider flow velocities and pressure loss (depending on the type of duct and valve used). The goal should be low velocities and minimal pressure loss.
If you find a good designer, you could agree on "increased sound insulation requirements" and then let the designer handle it.
In our design case, we have 35 m³/h (about 21 cubic feet per minute) through a floor outlet in the bedroom, which I do not find disturbing at all. If I could plan completely freely, I would probably aim for no more than 30 m³/h (about 18 cubic feet per minute). But—as mentioned above—it depends.
If you find a good designer, you could agree on "increased sound insulation requirements" and then let the designer handle it.
In our design case, we have 35 m³/h (about 21 cubic feet per minute) through a floor outlet in the bedroom, which I do not find disturbing at all. If I could plan completely freely, I would probably aim for no more than 30 m³/h (about 18 cubic feet per minute). But—as mentioned above—it depends.
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baumhaus8151 Nov 2017 19:36Our general contractor told us upon inquiry that including the basement in the controlled mechanical ventilation system (so far only the ground floor and upper floor, as previously mentioned) would be disproportionately expensive.
Do you have any experience with what additional effort might be required for the basement? From my point of view, I would initially say that ventilating the basement should be significantly cheaper since the ducts wouldn’t need to be as long and the system is already fully installed anyway. What are your thoughts on the costs?
Do you have any experience with what additional effort might be required for the basement? From my point of view, I would initially say that ventilating the basement should be significantly cheaper since the ducts wouldn’t need to be as long and the system is already fully installed anyway. What are your thoughts on the costs?
What exactly drives the price of a system like this (e.g., @Mycraft)?
It’s not the device itself; just adding a floor for 1,000 euros (€) (about $1,100) isn’t the main cost either. So how do system prices of 10,000 to 13,000 euros (€) (roughly $11,000 to $14,000) come about?
Floor outlets seem to be more expensive purely in terms of materials (nice grilles, etc.) than ceiling outlets. However, ceiling outlets require longer pipes in the case of, for example, the upper floor.
It’s not the device itself; just adding a floor for 1,000 euros (€) (about $1,100) isn’t the main cost either. So how do system prices of 10,000 to 13,000 euros (€) (roughly $11,000 to $14,000) come about?
Floor outlets seem to be more expensive purely in terms of materials (nice grilles, etc.) than ceiling outlets. However, ceiling outlets require longer pipes in the case of, for example, the upper floor.
As is often the case, both planning and on-site execution require significant effort.
Installing the ducts takes considerably longer when an entire additional floor is added... walls and ceilings will most likely need to be penetrated, which means for the general contractor either core drilling or deviations from the standard plan and new drawings for the concrete supplier.
Additionally, everything will likely need to be larger – both the system and the pipes – in order to meet the required air exchange rates.
Installing the ducts takes considerably longer when an entire additional floor is added... walls and ceilings will most likely need to be penetrated, which means for the general contractor either core drilling or deviations from the standard plan and new drawings for the concrete supplier.
Additionally, everything will likely need to be larger – both the system and the pipes – in order to meet the required air exchange rates.
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