Ventilating En suite - advice!

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okdk

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Hi all

My en suite (right of picture) is completely ‘internal’ - there’s no exterior walls. It’s right in the middle of my flat, and has zero ventilation.

It’s a period conversion, I’m on the ground floor and there’s 2 flats above me, so venting ‘upwards’ isn’t an option.

The closest exterior wall is on the left side of picture. I’ve been told that placing an inline extractor fan where the green circle is WON’T work - that a ducting run of 4.5m is too long for the extractor to pull from.

If anyone has any bright ideas I’d love to hear them! (Other than ‘move your bathroom’ which is no doubt correct but not an option, unfortunately)

Thanks
 

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You can get a more powerful ducted fan. Longer ducts need more power. Builders like to use cheap, ineffective fans.

In most cases a 110m diameter round duct is used, but you can also get rectangular ones that might be less obtrusive. Smaller ducts will obstruct flow and be noise. 125mm and 150mm ducts are sometimes used. Sometimes they can be run between joists or on top of or inside wall cabinets, such as in a kitchen. It is usually preferable to run the duct to the closest external wall. Ducts can be painted to match ceilings or walls or boxed in.

Ducts can also be run under floors and inside disused chimneys.

I wonder when the conversion was carried out, and what Building Regulations approval was given.

Where does the plumbing go?

Show us a floor plan please.
 
JohnD said:
You can get a more powerful ducted fan. Longer ducts need more power. Builders like to use cheap, ineffective fans.

In most cases a 110m diameter round duct is used, but you can also get rectangular ones that might be less obtrusive. Smaller ducts will obstruct flow and be noise. 125mm and 150mm ducts are sometimes used. Sometimes they can be run between joists or on top of or inside wall cabinets, such as in a kitchen. It is usually preferable to run the duct to the closest external wall. Ducts can be painted to match ceilings or walls or boxed in.

Ducts can also be run under floors and inside disused chimneys.

I wonder when the conversion was carried out, and what Building Regulations approval was given.

Where does the plumbing go?

Show us a floor plan please.
Click to expand...
Thanks!

It was done in the early 90’s I believe, and judging by the rest of the property, I don’t think ‘building regs’ were high up on their list.

I *think* the plumbing heads out as per this new picture.

Do you think a 150mm inline fan will have the necessary power? Or maybe I should just buy one and test it??

Thank you
 

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This is an example of a very quiet and powerful inline fan. It is not cheap. I'd usually say a bathroom with a steamy shower needs around 240 cu.m/hr flow. You will find several of this make from the link, such as the 350 which is not much more expensive than the 250. I recommend one with a timed run-on so it starts when you turn on the light switch, and continues for a period after turning the light off.


Because it is very quiet you can use it at night. In a flat you need to consider the neighbours.

There are cheaper ones, but not better.

The 4 inch ones have a snout you can remove to fit 5 inch duct

You might be able to run a duct under the floor.

There are graphs of flow reduction due to duct length and elbows, I will try to find one.

Edit
Try this
www.tlc-direct.co.uk

Fan Size Selector

www.tlc-direct.co.uk

Edit
Graph is in the "Technical" PDF
 
Last edited:
Or go across to the entrance hall and go 'out through the in door' or at least on that bit of wall.
 
JohnD said:
This is an example of a very quiet and powerful inline fan. It is not cheap. I'd usually say a bathroom with a steamy shower needs around 240 cu.m/hr flow. You will find several of this make from the link, such as the 350 which is not much more expensive than the 250. I recommend one with a timed run-on so it starts when you turn on the light switch, and continues for a period after turning the light off.


Because it is very quiet you can use it at night. In a flat you need to consider the neighbours.

There are cheaper ones, but not better.

The 4 inch ones have a snout you can remove to fit 5 inch duct

You might be able to run a duct under the floor.

There are graphs of flow reduction due to duct length and elbows, I will try to find one.

Edit
Try this
www.tlc-direct.co.uk

Fan Size Selector

www.tlc-direct.co.uk

Edit
Graph is in the "Technical" PDF
Click to expand...
That’s great, thank you.

Those fans look powerful. The shortest route to an outside wall is just under 5m - do you think these fans could handle that length of duct? If, for example, I placed the fan in the middle of the ducting? (2.5m from bathroom, 2.5m from exterior wall)
 
Yes, but I can't find the graphs of duct length and flow reduction.

If you have a shower, you need about 240 cu.m/hr flow after deducting for the duct length.

Cheap builders fans are usually about 80, and adequate for a washroom or single WC cubicle, but nothing more.
 
Make sure there's a 10mm gap under the door so it can pull air from the rest of the house. Ideally place the fan at the opposite end of the room from the door, then you get a complete diagonal sweep of the air in the room.

Extractors don't work in a sealed room, however powerful they are.
 
Ivor Windybottom said:
Extractors don't work in a sealed room, however powerful they are.
Click to expand...

Luckily, for those of us who don't live in submarines, such rooms do not exist.

Even if they did, the enormous volume of water vapour created as water evaporates would be removed by the extractor.
 
I have an ensuite off another room. The door between the two rooms has the gap underneath. The door into the main room doesn't.

If I leave the door into the room ajar then the extractor works OK. If it's closed then it achieves nothing.

A fan is just a blade that encourages the movement of the air. It's not a compressor so can't overcome a pressure difference - if there's nowhere for air to get in then it just won't extract, the air will just swirl in circles around the blade inside the duct.

This isn't a big deal in a victorian house with suspended floors, gaps under skirting boards and draughty windows. But in a modern building with concrete floors and decent windows then it's a very real issue.
 
If anyone is interested, here’s how it worked out. The fan, if anything, is possibly too powerful! Ventilation is really effective. And yes, I’m going to box it all in…
IMG_2639.jpeg
 
JohnD said:
This is an example of a very quiet and powerful inline fan. It is not cheap. I'd usually say a bathroom with a steamy shower needs around 240 cu.m/hr flow. You will find several of this make from the link, such as the 350 which is not much more expensive than the 250. I recommend one with a timed run-on so it starts when you turn on the light switch, and continues for a period after turning the light off.


Because it is very quiet you can use it at night. In a flat you need to consider the neighbours.

There are cheaper ones, but not better.

The 4 inch ones have a snout you can remove to fit 5 inch duct

You might be able to run a duct under the floor.

There are graphs of flow reduction due to duct length and elbows, I will try to find one.

Edit
Try this
www.tlc-direct.co.uk

Fan Size Selector

www.tlc-direct.co.uk

Edit
Graph is in the "Technical" PDF
Click to expand...
We got one! And it is brilliant.
 
You'd get a load of soot puffing out of the vent every time the wind blew!

Unless you lined it right to the top. Then you're talking full scaffolding, consent of the freeholder(s), etc etc.
 
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