How should mechanical ventilation from wall and floor be connected to the same fan?

[Ninhow]

Hello, so we are planning to tear down the basement and build it properly (Previous owners built gym room directly on concrete, leading to high moisture levels) by installing mechanical ventilation.

We’re on board with using Platon membrane, but we're a bit unsure about how to connect the fan and whether we need an Isola fan. They are super expensive, but they cover 110 m², which is exactly what we need. I've had some contact with Isola and their response was:

It is possible to have one fan and 2 dampers.
The fan drives both dampers (the fan can handle up to 110 square meters).

Now I'm a bit unsure about what they mean by the fan drives both dampers because the fan has only one inlet and one outlet and the same goes for the dampers. How would such a connection look like? It might be worth mentioning that the ventilation should ventilate both the walls and the floor.

I might be a bit ignorant, but I don't know much about ventilation and I'm trying to understand how this will look. Is it then that you connect two dampers with a T-connector at the exhaust which then goes to the fan? Because there I don't understand how the fan will drive both.

Grateful for all answers!

 

[Håbbe01]

No, the fan is not a magical variant except for the name and price. So, any quiet variant from the normal range will work. I usually buy my stuff at soliduct. Probably 125mm and it's important with an RPM regulator for the flow, and it's easiest to separate the wall and floor with one each. Platon offers, of course, the whole system with humidity monitoring and sizing plus materials for ++$

 

[Ninhow]

No, the fan is not a magical variant except for the name and price. So some quiet variant from the normal range works. I usually buy my stuff at soliduct. Probably 125mm and it's important with a speed controller for the flow and easiest by splitting the wall and floor with each. Platon of course offers the whole system with moisture monitoring and sizing plus materials for ++$

I see, thanks for the answer. We have a house with weak ventilation to - as exhaust, our plan is to start increasing the supply by adding some vents and tearing up the basement and laying Platon mats and fans to increase exhaust. The question is whether we need a fan on the upper floor as well. Do you have a fan that you recommend with a speed controller?

 

[Håbbe01]

Yes, you should have fresh air supply in every room except the toilet, and also on the upper floor with a separate fan in some toilet, maybe a Pax through the wall.

 

[BirgitS]

Yes, you should have supply air in every room except the WC, and the upper floor should also have its own fan in some WC, maybe a pax through the wall

No supply air in the kitchen, hallway, closet, storage, laundry room, toilets, and bathrooms, do you mean?

It is usually recommended to have exhaust fans in bathrooms, toilets, laundry rooms, and kitchens, as well as possibly in closets and storage if needed to ensure adequate airflow.

 

[Håbbe01]

Jo did not include all variants as it was not mentioned

 

[Ninhow]

Is there a way to measure the perfect supply and exhaust air? Or is it just the moisture content one should base it on?

 

[Ninhow]

Funnily enough, there are vents in all the rooms in the basement but not on the upper floor.

 

[Håbbe01]

Is it a basement one wonders if there are drainage problems so then it becomes like putting lipstick on a pig with Platon. Anyway, the moisture should be removed for the indoor climate with mold etc. So one should probably keep an eye on the Rh value over time and possibly increase the speed (flow) at the beginning. Preferably with increased temperature.

 

[Ninhow]

If it's a basement, one wonders if it's a drainage problem, so then it becomes like putting lipstick on a pig with Platon. Anyway, the moisture should be removed for the indoor climate with mold, etc. So one should have some control over the Rh value over time and possibly increase the speed (flow) initially, preferably with increased temperature.

It was drained 9 years ago, so I wouldn't think so. The upper floor doesn't have any moisture problems. The inspection only complained about the gyllestugan, which is just a part of the basement; otherwise, we should have received several rejections based on the basement itself.

Here's a picture of the ground floor:


It's the living room construction that had a high moisture content; they've built wooden frames on concrete. Nothing that was rejected based on the house's ventilation itself, except that the air was a bit low (I suspect it has to do with the couple that lived there being a bit older); they have also replaced the windows, and they lack vents, as well as I didn't see many vents either.

 

[Håbbe01]

A common mistake is to forget the syllpapp, allowing moisture to seep into the träregel.

 

[BirgitS]

Is there a way to measure the perfect supply and exhaust air? Or is it only the humidity ratio that one should consider?

There are standards that are based on what constitutes good ventilation for houses and the well-being of people.
at least 0.35 l/s and sqm
at least 4 l/s per person, most relevant for bedrooms in houses
15 l/s in bathrooms
10 l/s in kitchens, toilets, and laundry rooms

Curiously, there are vents in all the rooms in the basement but not on the upper floor.

The best ventilation system depends on how the house is heated and how the rooms are used.

In living rooms on the upper floor, it used to be drafty around the windows, so it was assumed that air came in there, and there was a lot of airing. Nowadays, windows are sealed to prevent unnecessary air from coming in, so supply air vents with controlled flow are needed instead.

In the basement, there are few or just small windows, and then there would be too little ventilation if relying on supply air around the windows. Especially in boiler rooms with an oil furnace that requires large quantities of supply air or in a laundry room where it got very humid when washing and drying. In the pantry, ventilation was installed to achieve refrigerator-like cold temperatures during the winter months.

 

[Ninhow]

There are standards based on what constitutes good ventilation for the well-being of houses and people.
at least 0.35 l/s per sqm
at least 4 l/s per person, most relevant for bedrooms in houses
15 l/s in bathrooms
10 l/s in kitchens, toilets, and laundry rooms

The best ventilation system depends on how the house is heated and how rooms are used.

In residential rooms on the upper floor, it used to be drafty around the windows, so it was assumed that air came in there, and there was a lot of airing. Nowadays, windows are sealed to prevent unnecessary air from entering, so supply air vents with controlled flow are needed instead.

In the basement, there are no or only small windows, resulting in inadequate ventilation if relying on air supply around the windows. This is especially true in boiler rooms with an oil burner that requires large amounts of supply air or in a laundry room, which becomes very humid when washing and drying. In the pantry, ventilation was used to achieve refrigerator-like conditions during the winter months.

Yeah, suspect that since the chimney hasn't been used since 2014, it can also worsen the air flow in the house.

 

[BirgitS]

Yes, a warm chimney stack makes the natural draft work much better.

 

[Ninhow]

Yes, a warm chimney stack makes the natural draft work much better.

Do you know if mechanical ventilation of the basement floor can interfere with the natural draft? I've read something about it causing drafts.