ᐅ Ventilation in New Construction (Central vs. Decentralized), Noise Disturbance
Created on: 20 Jun 2016 20:41
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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
S
Sebastian7929 Jun 2016 09:25It was about nighttime – operating through a heat exchanger during the day definitely makes sense.
The problem is that, at least with children, a house is never completely sealed, and terrace doors often stay open.
And then the place heats up...
The problem is that, at least with children, a house is never completely sealed, and terrace doors often stay open.
And then the place heats up...
@Bieber: I don't quite understand the answer right now. The goal was cooling, after all. It should be clear that it then necessarily has to be cooler outside (without any additional tools). And my point was simply that, in my opinion, mechanical ventilation with heat recovery is not suitable for bringing enough cool air into the house.
I feel like my post was somewhat overlooked in the overall discussion. That’s why I want to briefly highlight it again here. I would really appreciate any responses.
Kiri123 schrieb:
Thank you very much for all the replies here.
At the moment, I am leaning towards installing decentralized units from Meltem. Three units for the two-room system, so that one bathroom/WC is ventilated and another room (bedroom, children’s room, study) is ventilated. Then one standard unit in the living room.
That would put my material costs at around €5,000 (about $5,500), and I think the installation would be quick and straightforward (flush-mounted set → installed directly into the wall + laying 2-3 pipes).
This way, I cover all rooms at least partially, meet my minimum requirements, stay within budget, and avoid having to lay pipes throughout the whole house and open up ceiling soffits accordingly.
Am I being too optimistic here?
Are the installation costs actually higher so that I end up close to the cost of a central system? And do I perhaps even need to be careful about the structural integrity when laying pipes between rooms? Or are there more things to consider when installing the fans than simply covering all rooms? I think details like air exchange rates / air volumes are not fully considered here (but, as I said, I’m not opposed to ventilating with the window if necessary).
Also, I can imagine it would be unpleasant, for example, if I’m in the study and the demand ventilation in the guest WC activates, causing significantly more air to be pushed into the study or making the fan louder.
Furthermore: Do I need to cut ventilation slots in the individual doors so that air can circulate between rooms?
Thank you very much!
Kiri
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Bieber081529 Jun 2016 10:27BastianB schrieb:
And my point was simply that, in my opinion, mechanical ventilation with heat recovery is not suitable for bringing enough cool air into the house That may be true. For me, two points are essential:
1. With mechanical ventilation and (reversed) heat recovery, the interior doesn’t heat up as much in the first place, so the cooling demand is lower.
2. With automated control, the cooler periods at night are used more effectively than manual window ventilation allows (no one gets up at 2 a.m. just to ventilate for three hours …)
Sebastian79 schrieb:
so patio doors are often left open.
And then the house heats up… Exactly, that’s how it is…
S
Sebastian7929 Jun 2016 10:29Live in it first, then you can honestly share what difference it made for you.
An open window seems to provide more cooling at night than a mechanical ventilation system with a bypass... you can believe that or not.
An open window seems to provide more cooling at night than a mechanical ventilation system with a bypass... you can believe that or not.
I agree with Sebastian on this... however, I personally prefer not to invite animals or rain inside.
We don’t even have a sophisticated control system; we simply switch to summer ventilation mode when we go to bed. It’s rarely warmer than 23°C (73°F) at night, and if it is, a temperature drop around 2 a.m. happens even less often.
By the way, I can confirm the part about children... white walls and closed doors (front door, patio door, and for some visiting kids not even the bathroom door) can definitely be postponed for now.
We don’t even have a sophisticated control system; we simply switch to summer ventilation mode when we go to bed. It’s rarely warmer than 23°C (73°F) at night, and if it is, a temperature drop around 2 a.m. happens even less often.
By the way, I can confirm the part about children... white walls and closed doors (front door, patio door, and for some visiting kids not even the bathroom door) can definitely be postponed for now.
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