ᐅ Comparison Tests of Various Centralized Mechanical Ventilation Systems with Heat Recovery + Additional Questions
Created on: 1 Nov 2017 17:46
4
4Motion
Hello dear forum community,
I have a few questions about controlled residential ventilation systems that my own research online and in this forum haven’t helped me with. If you don’t want to read everything, feel free to jump straight to the questions.
First, about our situation: Two builders independently advised us against controlled residential ventilation. The first said it’s not necessary. He prefers to build with clay bricks (Poroton), which are vapor-permeable and allow excess moisture to move outside. He also applies hydraulic lime plaster to the walls, which can quickly absorb and release a lot of moisture and also absorb pollutants. Both the plaster and Poroton do not provide a breeding ground for mold or bacteria. Just occasional manual ventilation (opening windows briefly) is sufficient. He is also critical of the cleaning of duct systems. Well, that’s his opinion for now.
The other builder builds entirely with wood but argues similarly. He told us about customers who installed a controlled residential ventilation system just for safety but have now completely turned it off because they didn’t need it.
So initially, we were against controlled residential ventilation. After my research, however, I still want to have one. Personally, I’m somewhat negligent when it comes to ventilation. My wife, on the other hand, is a ventilation fanatic and always needs a lot of fresh air. She also always finds the air in prefabricated house showrooms very stuffy, which made us even more opposed to controlled residential ventilation. She actually prefers to ventilate manually all the time. Some windows in our home are even left slightly open for longer periods.
1. I am still a bit skeptical. Is there a statistic on what percentage of new builds have a controlled residential ventilation system?
2. To me as a layperson, all systems sound the same. Are there any comparison tests between different brands? Since controlled residential ventilation systems are so widespread, there should be tests similar to those for vacuum cleaners or kitchen appliances.
3. Who are the market leaders and which brands are rather niche players? So I can compare the top 5 myself.
4. Is it better to use round ducts with wide radii instead of flat ducts that sometimes bend sharply at 90°, to allow better cleaning? Or have you not considered that important?
I have a few questions about controlled residential ventilation systems that my own research online and in this forum haven’t helped me with. If you don’t want to read everything, feel free to jump straight to the questions.
First, about our situation: Two builders independently advised us against controlled residential ventilation. The first said it’s not necessary. He prefers to build with clay bricks (Poroton), which are vapor-permeable and allow excess moisture to move outside. He also applies hydraulic lime plaster to the walls, which can quickly absorb and release a lot of moisture and also absorb pollutants. Both the plaster and Poroton do not provide a breeding ground for mold or bacteria. Just occasional manual ventilation (opening windows briefly) is sufficient. He is also critical of the cleaning of duct systems. Well, that’s his opinion for now.
The other builder builds entirely with wood but argues similarly. He told us about customers who installed a controlled residential ventilation system just for safety but have now completely turned it off because they didn’t need it.
So initially, we were against controlled residential ventilation. After my research, however, I still want to have one. Personally, I’m somewhat negligent when it comes to ventilation. My wife, on the other hand, is a ventilation fanatic and always needs a lot of fresh air. She also always finds the air in prefabricated house showrooms very stuffy, which made us even more opposed to controlled residential ventilation. She actually prefers to ventilate manually all the time. Some windows in our home are even left slightly open for longer periods.
1. I am still a bit skeptical. Is there a statistic on what percentage of new builds have a controlled residential ventilation system?
2. To me as a layperson, all systems sound the same. Are there any comparison tests between different brands? Since controlled residential ventilation systems are so widespread, there should be tests similar to those for vacuum cleaners or kitchen appliances.
3. Who are the market leaders and which brands are rather niche players? So I can compare the top 5 myself.
4. Is it better to use round ducts with wide radii instead of flat ducts that sometimes bend sharply at 90°, to allow better cleaning? Or have you not considered that important?
Thank you for the answers! : )
Unfortunately, the statistics above don’t show what I wanted to know. They only compare different types of central mechanical ventilation systems.
The developer guarantees that their house won’t have mold issues, and my partner is already diligent about manual ventilation. So, we will probably build without a central mechanical ventilation system. However, I want a decentralized solution in both the bathroom and the large open-plan living-dining-kitchen area. Why? In the bathroom, an automatic system (one core drill hole for supply and exhaust air) that measures humidity. For the other room combination, which faces south, I want to be able to bring in cool air at night during summer without having the windows tilted open (there will be two fans working alternately from GetAir). What do you think?
Unfortunately, the statistics above don’t show what I wanted to know. They only compare different types of central mechanical ventilation systems.
The developer guarantees that their house won’t have mold issues, and my partner is already diligent about manual ventilation. So, we will probably build without a central mechanical ventilation system. However, I want a decentralized solution in both the bathroom and the large open-plan living-dining-kitchen area. Why? In the bathroom, an automatic system (one core drill hole for supply and exhaust air) that measures humidity. For the other room combination, which faces south, I want to be able to bring in cool air at night during summer without having the windows tilted open (there will be two fans working alternately from GetAir). What do you think?
Since I am not a building technician, I can only share the advice we received from our building consultant. The wall construction is Ytong, monolithic, meaning it is plastered and painted without any thermal insulation boards. It complies with standard energy-saving regulations, without any special KfW levels. His words. If you ventilate well, you don’t need anything else. But who actually does that? You also go on vacation sometimes, and since we are still building with moisture, it has to be removed in new buildings first. We build airtight, which we want and need to do for CO2 reduction and to lower energy costs.
Therefore, he would always install some kind of mechanical ventilation.
He offered us a controlled residential ventilation system from Zehnder, which I believe was about a 7.5% surcharge. Or a decentralized system from Helios, which was much cheaper—only about 1000 euros (approx. $) extra. You should know that our house is small, only 108 sqm (1160 sqft) of living space, all on one level. The Helios solution seemed sufficient for two people and one cat. It consists of an exhaust fan installed in the bathroom wall, running continuously, but switchable via a light switch if desired. It has a humidity sensor, so when the bathroom gets humid after showering, it increases speed. In every room, the window or windows have a slot with a control air module, a kind of forced fresh air intake. The fan extracts air, while fresh air softly enters through the windows. The result compared to our children’s house, with the same wall construction and no ventilation system, is striking. Their house quickly becomes stuffy, overheated, and the air feels strange. In our home, it is not drafty, but you still get the feeling of good air quality.
I would recommend such a system at a low cost to anyone. I feel well advised by the building consultant. Karsten
Therefore, he would always install some kind of mechanical ventilation.
He offered us a controlled residential ventilation system from Zehnder, which I believe was about a 7.5% surcharge. Or a decentralized system from Helios, which was much cheaper—only about 1000 euros (approx. $) extra. You should know that our house is small, only 108 sqm (1160 sqft) of living space, all on one level. The Helios solution seemed sufficient for two people and one cat. It consists of an exhaust fan installed in the bathroom wall, running continuously, but switchable via a light switch if desired. It has a humidity sensor, so when the bathroom gets humid after showering, it increases speed. In every room, the window or windows have a slot with a control air module, a kind of forced fresh air intake. The fan extracts air, while fresh air softly enters through the windows. The result compared to our children’s house, with the same wall construction and no ventilation system, is striking. Their house quickly becomes stuffy, overheated, and the air feels strange. In our home, it is not drafty, but you still get the feeling of good air quality.
I would recommend such a system at a low cost to anyone. I feel well advised by the building consultant. Karsten
I can confirm what was said about the exhaust ducts. In our case, a filter cap was placed directly over the exhaust duct vents (on the inside). These are then regularly cleaned with a vacuum cleaner. Maybe it’s because it’s a new building... but the filters always collect a significant amount of debris.
Per ventilation unit:
Per ventilation unit:
- Less headaches since no slowly accumulating poor air enters
- No worry about mold (mold can affect not only walls but also items in the room)
- The bedroom still smells fresh after waking up
- Indirectly: no unsightly solar panels on the roof
- No unpleasant temperature drop when ventilating
- Air can become somewhat drier in winter
- Electricity consumption (→ as I have learned from forum members, this is currently considerably too high in our case)
sven.conzi18 Nov 2017 15:21merlin83 schrieb:
I can confirm the issue with the exhaust ducts. In our case, a small filter cap was placed directly over the valve inside the exhaust ducts. These filters are then regularly cleaned with a vacuum cleaner. Maybe it’s because it’s a new building, but the filters always collect quite a bit of debris.
Per ventilation unit:
- Fewer headaches due to no slow infiltration of poor air quality
- No concern about mold (mold can grow not only on walls but also on objects in the room)
- The bedroom still smells fresh after getting up
- Indirect benefit: no unsightly solar panels on the roof
- No uncomfortable temperature drops when airing out
Cons:
- Air can become somewhat drier in winter
- Electricity consumption (--> as I’ve learned thanks to forum members, ours is currently significantly too high)
Dry air should be manageable or avoidable by supplementing the mechanical ventilation with heat recovery with an enthalpy exchanger.4Motion schrieb:
The developer guarantees us that his house cannot develop mold, and my better half is, in any case, a dedicated manual ventilator.Ah yes... he guarantees that his house cannot develop mold. How is that supposed to work? What he probably MEANS is that his warranty only applies as long as mold damage is unlikely to occur.
And does your wife also get up every few hours at night to create cross-ventilation? Hardly... You sleep best at night, which only works well if the CO2 levels don’t rise uncontrollably. This requires sufficient ventilation.
So let’s be honest! With today’s airtightness of houses (well, as long as airtightness is not ruined by tilted windows), anything other than mechanical ventilation is just an illusion, whether it concerns mold or “just” poor air quality. Decentralized units are possible, but when correctly designed to meet the required airflow (in new builds) for an average single-family home (150 m² (1,615 sq ft)), they are most likely only marginally cheaper.
In any case, ALWAYS have ventilation if at all possible!
4Motion schrieb:
We will probably build without a central controlled residential ventilation system.Bad idea... better to keep it simple in the bathroom and kitchen or something like that... I can only agree with the previous posters.
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