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
D
Deliverer21 Jun 2016 14:26nordanney schrieb:
Why should I ventilate manually if I have a ventilation system for that? That's true. Ideally, you wouldn’t need to. However, the original poster likes to keep the windows open, so in my opinion, they don’t really need an expensive ventilation system.
nordanney schrieb:
P.S. One more question about the high maintenance effort. What do you mean by that? Well—every system requires cleaning and maintenance (filter replacement, cleaning/disinfection…). The bigger, more expensive, and more complex the system, the higher the ongoing costs. For some people (hay fever sufferers), it’s worth it; for others (people living in rural areas who ventilate naturally), it’s not.
My choice was also strongly influenced by the additional cost of about 10,000 euros (which would only pay off after nearly 30 years). It’s important not only to compare the pure system costs but also the changes to structural engineering, ceiling height, cutouts in cladding, and so on.
S
Sebastian7921 Jun 2016 14:29Kiri123 schrieb:
-more complex planning including ceiling suspensions and boxing-in of ducts
-(I heard from a supplier of decentralized ventilation systems: as soon as I turn up the ventilation in the living room, more warm air is pushed into the bedroom → not desirable)For example, when installing ducts in or on raw concrete ceilings, no boxing-in or ceiling suspension is necessary. And you can't just "turn up" the ventilation in one room—it always increases everywhere.
Why would you insulate and seal a house tightly only to drill holes in the exterior walls afterward? I will never understand that approach with decentralized systems in a new build—let alone the noise factor.
D
Deliverer21 Jun 2016 14:32Sebastian79 schrieb:
Why would you go through the effort of insulating and sealing a house airtight, only to drill holes in the exterior walls afterward? Because otherwise you’d suffocate?!
Fresh air is necessary with all systems. I don’t see much difference there.
S
Sebastian7921 Jun 2016 14:33That referred to decentralized systems (and especially those) without heat recovery...
Cleaning usually only takes a few minutes per month. I suspect that having windows open lets more dirt into the house, which increases the cleaning effort for the building itself. Hardly anyone will leave their windows open permanently, meaning that if you come home after a few hours, the air can be really stale (I once turned off the ventilation system as a test during a few hours of absence – definitely won’t do that again).
At first, we wanted the solution with “central exhaust + decentralized supply air,” but for various reasons, we decided on a fully central system instead. Although I lack comparison options, I am very satisfied with this setup.
At first, we wanted the solution with “central exhaust + decentralized supply air,” but for various reasons, we decided on a fully central system instead. Although I lack comparison options, I am very satisfied with this setup.
D
Deliverer21 Jun 2016 14:39Sebastian79 schrieb:
That referred to decentralized systems (and especially) without heat recovery... My answer was the same. Why should it be better to have one large hole instead of five smaller ones?
Regarding heat recovery, I already mentioned that with heating costs of 1000 to 1500 per year, it is hardly possible to save enough for heat recovery to be cost-effective.
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