ᐅ Ventilation in New Construction (Central vs. Decentralized), Noise Disturbance
Created on: 20 Jun 2016 20:41
K
Kiri123
Hello everyone,
I am currently considering the ventilation system for our planned new build (details: Kfw 70, 2 full floors + basement + unheated attic, hipped roof, 200m² (2,150 sq ft) living space). We live in a rural area and like to keep the windows open sometimes, so we don’t necessarily have to rely entirely on mechanical ventilation.
I am torn between a central controlled mechanical ventilation system with heat recovery, a central exhaust with decentralized supply air, and decentralized supply/exhaust with heat recovery. My requirements are:
• Ventilation of bathrooms (master bathroom, children’s bathroom without windows, and guest toilet without windows) with demand-controlled ventilation based on usage
• I want to avoid having to open windows every few hours while still maintaining high indoor air quality
• Not too noisy, as I am very sensitive to noise when trying to sleep
• I am also sensitive to dry air; for example, I cannot tolerate air from air conditioning or sports halls very well
Below are the pros and cons of each system as I see them:
Central Controlled Mechanical Ventilation with Heat Recovery
+the most mature system
-expensive (I estimate about 10,000 to 13,000 Euros)
-more complex planning, including suspending and boxing in ducts
-(I heard from a provider of decentralized ventilation systems: as soon as I turn up the ventilation in the living room, more warm air is blown into the bedroom – not desirable)
-the indoor air quality in the prefabricated houses with controlled ventilation that we visited was always poor. That makes me skeptical
Central Exhaust with Decentralized Supply Air
+cheaper (maybe 2,000 to 3,000 Euros?)
+should meet minimum requirements
-energy wasted (or can I reuse the heat energy somehow? I am planning to install an air-water heat pump for heating and hot water production. Maybe the heat can be used here in a useful way). I was advised against a complete exhaust heat pump. Perhaps combined exhaust/fresh air heat pumps exist?
-cold air from decentralized supply? (I have read that with proper planning this is no problem because the supply air mixes “appropriately” with the existing indoor air)
-somewhat contradicts the idea of energy-efficient houses. Still, it’s probably more efficient than constantly having windows tilted open.
Decentralized Ventilation with Heat Recovery
+If I simply install one of these ventilators in the living-dining area, the master bathroom, and the children’s bathroom (+ exhaust in the toilet), the minimum requirements should be met. I estimate about 3,000 Euros (1,000 Euros per unit)
-if I want to cover all other rooms to avoid window ventilation entirely, it gets more expensive (maybe ~8,000 Euros) and:
-I would have many holes in the building envelope
-I hesitate to install these devices in bedrooms or children’s rooms because I think they may be too noisy.
Could you please help me with the decision? Maybe by sharing your experience or confirming or disproving some of my points? I would also like to see different ventilators in practice. Do you have any tips? I heard it might be possible somewhere in Berlin, but I live in the postal code area 5xxxx.
I look forward to your opinions.
Kiri
I am currently considering the ventilation system for our planned new build (details: Kfw 70, 2 full floors + basement + unheated attic, hipped roof, 200m² (2,150 sq ft) living space). We live in a rural area and like to keep the windows open sometimes, so we don’t necessarily have to rely entirely on mechanical ventilation.
I am torn between a central controlled mechanical ventilation system with heat recovery, a central exhaust with decentralized supply air, and decentralized supply/exhaust with heat recovery. My requirements are:
• Ventilation of bathrooms (master bathroom, children’s bathroom without windows, and guest toilet without windows) with demand-controlled ventilation based on usage
• I want to avoid having to open windows every few hours while still maintaining high indoor air quality
• Not too noisy, as I am very sensitive to noise when trying to sleep
• I am also sensitive to dry air; for example, I cannot tolerate air from air conditioning or sports halls very well
Below are the pros and cons of each system as I see them:
Central Controlled Mechanical Ventilation with Heat Recovery
+the most mature system
-expensive (I estimate about 10,000 to 13,000 Euros)
-more complex planning, including suspending and boxing in ducts
-(I heard from a provider of decentralized ventilation systems: as soon as I turn up the ventilation in the living room, more warm air is blown into the bedroom – not desirable)
-the indoor air quality in the prefabricated houses with controlled ventilation that we visited was always poor. That makes me skeptical
Central Exhaust with Decentralized Supply Air
+cheaper (maybe 2,000 to 3,000 Euros?)
+should meet minimum requirements
-energy wasted (or can I reuse the heat energy somehow? I am planning to install an air-water heat pump for heating and hot water production. Maybe the heat can be used here in a useful way). I was advised against a complete exhaust heat pump. Perhaps combined exhaust/fresh air heat pumps exist?
-cold air from decentralized supply? (I have read that with proper planning this is no problem because the supply air mixes “appropriately” with the existing indoor air)
-somewhat contradicts the idea of energy-efficient houses. Still, it’s probably more efficient than constantly having windows tilted open.
Decentralized Ventilation with Heat Recovery
+If I simply install one of these ventilators in the living-dining area, the master bathroom, and the children’s bathroom (+ exhaust in the toilet), the minimum requirements should be met. I estimate about 3,000 Euros (1,000 Euros per unit)
-if I want to cover all other rooms to avoid window ventilation entirely, it gets more expensive (maybe ~8,000 Euros) and:
-I would have many holes in the building envelope
-I hesitate to install these devices in bedrooms or children’s rooms because I think they may be too noisy.
Could you please help me with the decision? Maybe by sharing your experience or confirming or disproving some of my points? I would also like to see different ventilators in practice. Do you have any tips? I heard it might be possible somewhere in Berlin, but I live in the postal code area 5xxxx.
I look forward to your opinions.
Kiri
N
nordanney21 Jun 2016 14:47Deliverer schrieb:
Well – every system requires maintenance and cleaning. (Filter replacement, cleaning/disinfection...) The larger, more expensive, and more complex the system, the higher the ongoing costs. For some people (hay fever sufferers), it's worth it; for others (residents in well-ventilated rural homes), it’s not. Vacuum it once a month, replace the coarse filter once a year (costs a few euros), and replace the fine filter if needed (about €25, so far only once in two years).
That’s all that’s required so far – so ongoing costs are not a valid argument against a central mechanical ventilation system with heat recovery.
Are decentralized systems really filter-free? That would be a major disadvantage – I definitely don’t want to bring pollen and outdoor dust into the house unnecessarily.
D
Deliverer21 Jun 2016 14:52If that's all there is, then the systems probably aren't that different. Until now, I assumed that a service technician would need to attend to them every one or two years.
S
Sebastian7921 Jun 2016 14:53They are quite different... the operating principles are completely different, which also affects the comfort for the user.
D
Deliverer21 Jun 2016 14:57I meant, the cleaning effort is pretty much the same. It’s clear, though, that these are very different systems.
And one thing is also clear: the original poster knows as much as before asking the question!
And one thing is also clear: the original poster knows as much as before asking the question!
In a new build like the one the original poster (OP) is planning, I would recommend a central mechanical ventilation system with heat recovery. The reasons – including comfort – have already been mentioned here, and I can confirm them from personal experience.
My advice to the OP would be to choose a system that can increase indoor humidity during winter. The system I have does not have this feature, and the air becomes quite dry.
Aside from that:
- With a properly sized system of this type, the air feels fresh and comfortable. In show homes, you often see windows open and constant coming and going. In those cases, the ventilation system doesn’t provide noticeable benefits… which makes sense.
- Maintenance effort is minimal. I clean the main filters once a year and the exhaust air filters in the ceiling 3-4 times per year (effort level = very easy; I can still do it even after hip surgery).
- Outside the cold months, the system has the advantage that fewer allergens and pollen enter the house. But that’s a bit irrelevant – even we have windows open and the system turned off at times. Features like a summer bypass are often overrated; they provide little to no benefit since it’s *not* air conditioning (unless the system includes that option, which some do). Also, you can set the system to “exhaust only,” allowing some (cooler, nighttime) fresh air to enter via tilted windows.
- Drafts and noise aren’t an issue in my view. Given the necessary air exchange rates, airflow velocities through the selected duct sizes are minimal. Plus, air intakes are best located in front of windows—not directly at beds, under tables, or similar spots. This is a matter of good planning, correct sizing, and proper adjustment. We have done this and it works very well.
As I mentioned elsewhere here, if I had to build again, I would never build without mechanical ventilation. I am enthusiastic about the system. We mitigate the downside of dry air in winter with “hanging laundry” and a humidifier to keep it tolerable.
In winter (generally all year here in Velbert, haha, a little insider joke related to the weather thread), especially when you don’t want to open windows and heat the garden, the overall indoor climate is very good. The entire air volume is exchanged roughly every 2 hours. With heat recovery, losses are low (to clarify, there are NO heat gains as some believe—it’s just more cost-effective than ventilating with open windows).
Best regards
Thorsten
My advice to the OP would be to choose a system that can increase indoor humidity during winter. The system I have does not have this feature, and the air becomes quite dry.
Aside from that:
- With a properly sized system of this type, the air feels fresh and comfortable. In show homes, you often see windows open and constant coming and going. In those cases, the ventilation system doesn’t provide noticeable benefits… which makes sense.
- Maintenance effort is minimal. I clean the main filters once a year and the exhaust air filters in the ceiling 3-4 times per year (effort level = very easy; I can still do it even after hip surgery).
- Outside the cold months, the system has the advantage that fewer allergens and pollen enter the house. But that’s a bit irrelevant – even we have windows open and the system turned off at times. Features like a summer bypass are often overrated; they provide little to no benefit since it’s *not* air conditioning (unless the system includes that option, which some do). Also, you can set the system to “exhaust only,” allowing some (cooler, nighttime) fresh air to enter via tilted windows.
- Drafts and noise aren’t an issue in my view. Given the necessary air exchange rates, airflow velocities through the selected duct sizes are minimal. Plus, air intakes are best located in front of windows—not directly at beds, under tables, or similar spots. This is a matter of good planning, correct sizing, and proper adjustment. We have done this and it works very well.
As I mentioned elsewhere here, if I had to build again, I would never build without mechanical ventilation. I am enthusiastic about the system. We mitigate the downside of dry air in winter with “hanging laundry” and a humidifier to keep it tolerable.
In winter (generally all year here in Velbert, haha, a little insider joke related to the weather thread), especially when you don’t want to open windows and heat the garden, the overall indoor climate is very good. The entire air volume is exchanged roughly every 2 hours. With heat recovery, losses are low (to clarify, there are NO heat gains as some believe—it’s just more cost-effective than ventilating with open windows).
Best regards
Thorsten
nordanney schrieb:
Are decentralized systems without filters? That would be a significant drawback – I definitely don’t want to bring pollen and dust from outside into the house.Of course, I can’t speak for all decentralized systems.
With ours, you can choose between dust filters or pollen filters (each available in different classes).
Our system prompts us to replace the filters approximately every three months. The pollen filters definitely need to be replaced, while the dust filters can be cleaned by hand or in a washing machine (inside a bag).
So far, we have only used dust filters, which we washed three times and replaced on the fourth. Ten dust filters cost about 30 euros (roughly $33), if I remember correctly (we need them for six fans during replacement). Once the supply is used up, we plan to buy one or two square meters of filter fleece and cut the filters ourselves. I think that will be even cheaper.
Although my wife is allergic, we haven’t had to use pollen filters so far.
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