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
Electricity needs to be routed everywhere, control systems, core drillings...
I’m still not entirely sure about the doors... our doors are standard, and when I turn on the exhaust fan in the bathroom, air already flows through the door gap; I don’t understand why this wouldn’t be sufficient.
If it’s decentralized, I think I would just install a unit in every room... which wouldn’t be significantly more expensive in terms of materials.
I’m still not entirely sure about the doors... our doors are standard, and when I turn on the exhaust fan in the bathroom, air already flows through the door gap; I don’t understand why this wouldn’t be sufficient.
If it’s decentralized, I think I would just install a unit in every room... which wouldn’t be significantly more expensive in terms of materials.
B
Bieber081528 Jun 2016 21:35Sebastian79 schrieb:
And what good does it do? Warm supply air can be cooled by cooler exhaust air, so the house heats up more slowly. Once it gets cooler at night (compared to the indoor or desired temperature), the heat exchanger is bypassed and the cool supply air is brought directly into the house. This is all controlled by temperature, without any effort from the (sleeping) occupants, who can sleep comfortably instead of opening or closing windows.
Mycraft schrieb:
Normally in summer, the bypass is generally open... Or automatically controlled by temperature.
Curly schrieb:
Does this system have to be installed directly where the ducts go through the exterior wall, or is it possible, for example, to run a duct through another room to the outside? Typically, the supply and exhaust ducts are quite large and also include silencers. Talk to a planner or designer about this.
@Curly
The supply and exhaust air ducts should be as short as possible and can be located on the same exterior wall. The required distance between them is specified in the system’s documentation, but is usually around 2 meters (6.5 feet). With combined Vallox wall hoods, the supply and exhaust pipes can even be installed directly next to each other through the external wall.
If the system has a reasonably intelligent control, the bypass remains open continuously during the summer.
The supply and exhaust air ducts should be as short as possible and can be located on the same exterior wall. The required distance between them is specified in the system’s documentation, but is usually around 2 meters (6.5 feet). With combined Vallox wall hoods, the supply and exhaust pipes can even be installed directly next to each other through the external wall.
Bieber0815 schrieb:
Or temperature-controlled automatically.
If the system has a reasonably intelligent control, the bypass remains open continuously during the summer.
Last summer, I used the heat exchanger the other way around (automatically) to cool the outside air. Although the cooling effect was small, it helped slow down the warming of the house. I didn’t have any issues with condensation (since the air never got colder than the indoor temperature, and the system has a drain).
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Sent from mobile
B
Bieber081529 Jun 2016 07:13Mycraft schrieb:
If the system is controlled reasonably intelligently, the bypass remains open throughout the summer. Saruss schrieb:
Last summer, I actually did the opposite through the heat exchanger (automatically) and cooled the outside air. That’s exactly what I mean... heat recovery works in both directions.
S
Sebastian7929 Jun 2016 07:26Bieber, you described it very much like the manufacturers’ advertising.
I’m familiar with it because we have the same setup – and I can tell you, it hardly makes a difference. After all, it’s not air conditioning.
And normally, sound attenuators are not installed in the outdoor ducts – only optionally in the exhaust air.
By the way, we have 11.5 meters (38 feet) of exhaust duct and 50 centimeters (20 inches) of fresh air duct.
I’m familiar with it because we have the same setup – and I can tell you, it hardly makes a difference. After all, it’s not air conditioning.
And normally, sound attenuators are not installed in the outdoor ducts – only optionally in the exhaust air.
By the way, we have 11.5 meters (38 feet) of exhaust duct and 50 centimeters (20 inches) of fresh air duct.
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