Need Exhaust Fan That Has Soundproof Properties

[Trdat]

Long story short, I need an intake fan to bring in fresh air(oxygen) inside my apartment in which the carbon monoxide increases once there is more than one person inside. I know, why don't I open windows but the air quality is horrendous in my country during winter so I am looking at an exhaust fan that has a HEPA filter so filtered air is brought inside. I know basic forms of this exist however I need something that has soundproof properties through the length of the fan tubing.

Now the problem is that I will put this fan in my corridor which has open windows however I do not want general noise from the corridor to leak into the apartment from that opening. T

The wall is about 60cm thick so the fan will need to be approximately that in length, is there such a thing available in the market that will draw air inside fromoutside through a HEPA filter but also has some soundproofing qualities through the tube?

I do have other options I have 3 exhaust ventilation, kitchen, bathroom and a spare outlet for gas which I am not allowed to touch. With this option air can be sucked in through these points air from the roof so no sound however I can't see how these can be used. Don't want to be pulling in air from the kitchen ventilation as I will pull in all the oil and grease that is being pulled out. For now, I am exploring this option. Any ideas on a product like this?

I know exhaust fans such as this exist just not sure if they have soundproof properties.

 

[Danish ear]

Don't know the legislation in your country but here in Denmark, what you're asking for, would require a central ventilation unit with both supply-, return-air and a heat exchanger. A HEPA-filter needs 2-stage pre-filtering to get good filter economy, this is not something a domestic fan can cover, due to the relative high pressuredrop of the three filters.
A typical domestic fan running at medium speed need as a minimum 1200mm(length) duct silencer to bring noise levels down to <25dB(A).
Remember that air taken from outside needs to be preheated to avoid thermal discomfort.

 

[nerdstrike]

Supplemental thoughts that may or may not help:

1. If your walls are wooden framed, mounting a fan to the wood without isolation will project surprising amounts of vibration noise through to different parts of the house.
2. Some "extractor" type fans can function very poorly with dense filters. They don't produce meaningful static pressure, so a HEPA filter or similar would reduce flow down to nothing. Buy with care.
3. Stating something hopefully obvious: Humans don't biologically produce carbon monoxide (ignoring the infinitessimal), usually it comes from poor combustion. If the CO is coming from outside, a HEPA filter won't keep it out.

You describe a tricky scenario!

 

[Mnyb]

Maybe OP means CO2 as we are breathing aka carbon dioxide , a simple misunderstanding .

I'm unfamiliar with local building standards , but some kind of basic ventilation must exist already ?

 

[Fred H]

How about a small HRV (heat recovery ventilator)? Something like this, this, or this. They switch between two tiny ventilators (usually in different rooms) so that a heat-absorbing mass reduces the heat or cooling loss, and do a bit of filtering. The better ones only operate when the air should be replaced. All are supposed to be "quiet", but their fan noise depends on how hard they are working.

 

[Trdat]

Don't know the legislation in your country but here in Denmark, what you're asking for, would require a central ventilation unit with both supply-, return-air and a heat exchanger. A HEPA-filter needs 2-stage pre-filtering to get good filter economy, this is not something a domestic fan can cover, due to the relative high pressuredrop of the three filters.
A typical domestic fan running at medium speed need as a minimum 1200mm(length) duct silencer to bring noise levels down to <25dB(A).
Remember that air taken from outside needs to be preheated to avoid thermal discomfort.

Don't worry about legislation nor about heat exchange, I just want to drag clean air in.

Okay so bare minimum I need your saying is a 2 stage filteration and your saying a domestic fan can't over that in what sense? Not powerful enough? But, thats fine, I know I will need a more powerful fan so that's fine.

But if you say I need 120cm yeh that wont work the wall is about 60cm thick.

 

[Trdat]

Maybe OP means CO2 as we are breathing aka carbon dioxide , a simple misunderstanding .

Sorry, yeh just mean the C02 we breathe out. I have no idea why i said carbon monoxide school boy error.

I'm unfamiliar with local building standards , but some kind of basic ventilation must exist already ?

I got windows but the C02 levels increase dramatically with more than one person and in winter opening windows means an increase of PM2.5 from 0 to 50-80 in about 5 min which I want to try and avoid.

 

[Trdat]

Supplemental thoughts that may or may not help:

1. If your walls are wooden framed, mounting a fan to the wood without isolation will project surprising amounts of vibration noise through to different parts of the house.

The walls are not wooden they are concrete or block. Its a Soviet Era apartment.

1. Some "extractor" type fans can function very poorly with dense filters. They don't produce meaningful static pressure, so a HEPA filter or similar would reduce flow down to nothing. Buy with care.

This point is interesting, are you saying that what I need or want might not actually be able to bring air inside?

 

[Trdat]

Don't know the legislation in your country but here in Denmark, what you're asking for, would require a central ventilation unit with both supply-, return-air and a heat exchanger. A HEPA-filter needs 2-stage pre-filtering to get good filter economy, this is not something a domestic fan can cover, due to the relative high pressuredrop of the three filters.
A typical domestic fan running at medium speed need as a minimum 1200mm(length) duct silencer to bring noise levels down to <25dB(A).
Remember that air taken from outside needs to be preheated to avoid thermal discomfort.

Actually, can you post me a link or something of what you would recommend for a wall of 1200mm so I can get an idea of what I am looking at?

And are you saying that if the length of the fan(not domestic) is 1200mm it could potentially bring in air from outside with a noise reduction of 25Dba? And is this noise reduction from only the fan or the sound emanating from outside that might leak through that ducting?

 

[Trdat]

How about a small HRV (heat recovery ventilator)? Something like this, this, or this. They switch between two tiny ventilators (usually in different rooms) so that a heat-absorbing mass reduces the heat or cooling loss, and do a bit of filtering. The better ones only operate when the air should be replaced. All are supposed to be "quiet", but their fan noise depends on how hard they are working.

I have come across this idea this is my last resort however my worry about noise is not so much from the fan itself rather noise from outside that will leak in from that hole hence why I was wondering if there is such thing as a fan or something similar to what you have shown that reduces sound coming from outside through that hole or ducting?

 

[Devnull]

I have to ask why are you concerned about the CO2 levels? Have you actually measured them?

 

[DVDdoug]

Try researching how soundproof recording studios deal with air flow and HVAC. I would assume that the air flow needs a long, indirect, curved or folded, and insulated path. But I found this.

 

[somebodyelse]

I'm also puzzled by the CO aspect, and the nature of the poor air quality outdoors - the HEPA filter will only remove particulates, so whether it would help depends on what's making the outdoor air poor.

I think the 1200mm refers to the length of the duct silencer/attenuator not the length of the fan. The attenuator is to reduce the sound of the fan and/or sound from outside.

 

[DVDdoug]

I'm also puzzled by the CO aspect, and the nature of the poor air quality outdoors

I believe he's got two issues - Exhausting the air with CO2 and filtering the incoming air.

 

[Pareto Pragmatic]

Now the problem is that I will put this fan in my corridor...

Remember, the fan can be anywhere. One end of a tube, the other end, in the middle. A different location can make a big difference in noise that affects others.


You do NOT need a lot of flow, just a steady flow. A steady flow will keep things from building up. To clear a lot of volume quickly takes a lot more. So aim to keep things from building up.

First thing I would check would be to see if the kitchen fan and/or the bathroom fan will create enough flow from the building to outside. Given the type of building, I am going to guess you get flow into your place from the hallway via the door. If you are OK with the inside air, no need to filter.

Then you can see about making those fans less noisy. Or one of them.

 

[Trdat]

I have to ask why are you concerned about the CO2 levels? Have you actually measured them?

Yes, I have. Once there is more than one person in the apartment it jumps to over 1000 and can keep climbing. I usually open windows, does the trick but I am exploring other options for winter.

 

[Trdat]

I'm also puzzled by the CO aspect, and the nature of the poor air quality outdoors - the HEPA filter will only remove particulates, so whether it would help depends on what's making the outdoor air poor.

That is a great question I would say its a combination of the general stuff but mainly households still burning wood to keep warm. Which bring another problem, I have neighbors burning that would close by where the smoke enters directly in. However, this is in snippets but even then when it stops the general air quality is still bad. I mean, I can check there are monitors across the entire city which provide stats.

I think the 1200mm refers to the length of the duct silencer/attenuator not the length of the fan. The attenuator is to reduce the sound of the fan and/or sound from outside.

That is good news if it attenuates sound from outside as well, and the extra 60cm can sit inside my apartment so it might work.

 

[Danish ear]

Fred H is on to something, though I never recommend this solution to customers. They are a little more noisy than a centralised air handling unit and the energy consumption is higher pr. flowrate. As I recall they come standard with a G4 filter that only protects the unit itself and does nothing to protect your lungs (particle size). Never the less in your situation the wall fans can probably reduce the Co2 levels in your room. 600mm of concrete, that's a serious drilling job.

 

[somebodyelse]

That is good news if it attenuates sound from outside as well, and the extra 60cm can sit inside my apartment so it might work.

It isn't an extra 60cm - the flow would be outside -> fan -> attenuator (the long cylinder) -> heat exchanger, or something like that.

That is a great question I would say its a combination of the general stuff but mainly households still burning wood to keep warm. Which bring another problem, I have neighbors burning that would close by where the smoke enters directly in. However, this is in snippets but even then when it stops the general air quality is still bad. I mean, I can check there are monitors across the entire city which provide stats.

So wood smoke will be particulates which the filter will remove, and gases including carbon dioxide, carbon monoxide and unburnt volatiles, which won't be removed. An activated carbon filter would help with volatiles (smell) but not CO or CO2. You might end up making the CO problem worse not better. Where's the indoor CO source? An open fire, or exposed gas appliance like a gas hob? You might be better dealing with the source instead of treating the symptom. Do the monitor stats include specific pollutant levels, or just an air quality number?

 

[Devnull]

Instead of pulling air from outside have you considered pulling air or circulating from the inside common area of your building. As an experiment what happens if you turn on an existing exhaust fan while the hallway door is cracked?