Extract Fan Dilemma

[securespark]

I have a small en-suite, around 1.7m x 1.6m.

Currently, there is a Vent Axia 4" fan in the wall opposite the shower enclosure.

It extracts 108 m³/h.

The en-suite gets steamy and the wall near the fan gets damp.

I am going to ask a roofer to fit a vent over the shower enclosure up through the warm flat roof for more direct exhaust of the moist air.

I would like to fit the most powerful sub-6 inch fan I can. My plan is to use a 5 inch Soler and Palau model exhausting 180 m³/h.

I like to over-engineer things. Do you think that is overkill?

Would you just refit the 108m³/h Vent Axia fan instead?

Cheers.

 

[stem]

Personally I would be with you on this one. I feel a more powerful fan close to the source of the steam is the best solution to help keep it contained as much as possible to the shower area and reduce its spread to elsewhere.

If you use a run-on timer you could try reducing the time it's on for because of the extra extraction rate. Then your electricity use and loss of heat from the room in the winter wouldn't increase too much.

 

[Murdochcat]

How much air flow do you get under the door ? This is very important. And you'll always get steam in a shower room

 

[securespark]

Thanks, people.

I'm going to slice a bit more off the bottom of the door to allow more airflow.

 

[securespark]

Just been speaking to a spark who reckons the fan HAS to be SELV to go in a shower cubicle.

He also believes that Zones run from the highest point of the shower tray, not from FFL

The actual distance from FFL to the ceiling is 2.27m. The fan front plate is 30mm thick, so he reckons it is inside Zone One by 10mm.

Regardless, if the fan is IPX4 minimum, it's OK in Zone Two or Zone One for that matter.

The fan I want is IP45.

The same electrician said my replacement recessed lights in the lounge were a fail, as they are not the can type. But they are fire rated, even though they don't need to be.

What are they teaching kids these days?

Need another electrician!

 

[ericmark]

In the main, it is the fan control which causes the problem. The idea of a vent one end of the room and fan the other to suck the air out of the room, can make the room rather cool, clearly any air blown out, needs replacing.

For a bath, one could be in the room ½ hour or more. But for a shower, 15 minutes is more the norm, so if you don't move the air during the shower, most of the water vapour will condense within the shower cubical. And then after the shower, one uses the fan to remove the water not condensed. So the timer wants to start when you leave the room, not when you go in.

I had a problem with last house, but not with mothers, and not with this one, so I sat back and thought why? And realised the main problem was the shower was in the bath, so a large gap at bottom of the shower door, and gap at top, so the chimney effect circulated the water vapour around the room. Mother's house was a wet room, so no shower cubical or curtain, so no air circulation, and in this house the shower cubical seals at the bottom.

So stop the circulation and one also stops the mould problem.

 

[JohnD]

If you have room anywhere, the ducted inline fans are more powerful, and the S&P ones well made with the ball bearing motor. They have the advantage of being quiet enough that the timed overrun is not a nuisance.

For a steamy shower, 240 cu.m/hr is a better flow rate

I'm not keen on making holes in roofs that need to keep the rain out.

 

[Murdochcat]

Re the shower room - improve the air flow under the door and see what happens

As for the downlights in the lounge - as long as the room above is part of your home there is no need for fire rated units.

Beware, as you have found out, there are some uneducated muppets out there.

 

[EFLImpudence]

Re the shower room - improve the air flow under the door and see what happens

WTF? Leave the door open a little bit to see what happens before cutting it.

 

[securespark]

Finalising with the roofer what size fan duct to fit.

They are saying only 4 and 6" ducts are available. I'm with John on this and 240m³/h ish would be a better rate.

There is a 4" fan that will go to 300, but it is an in-line unit, so won't fit.

My preference is 5". Surely there is a 5" duct out there suitable for a warm flat roof?

I can't find any 4" ceiling mounted fan that goes much over 100 cu m/h.

Murdoch and EFLI...Thanks, leaving the door open a crack works well, so I shall slice un petit peu off the bottom of the door.

 

[securespark]

Looked at the Xpelair Simply Silent 6" fan which has a good output, but I'm not sure if it is minimum IP44, whether it can be ceiling mounted, how much it protrudes from the ceiling and whether you can have a round fascia rather than a square one. Will ring them in a bit.

 

[chivers67]

I used some anti condensation paint on the walls of our bathroom Perma protect. The wall is warmer to touch & we get less condensation as a result.

 

[JohnD]

I have an S&P Silent wall fan 4 inch which I remember can go in zone, I will look to see if they have a 6 inch version

 

[JohnD]

Here we are. IP45, ball bearing motor, timer, 280 cu.m

Silent 300 CRZ 6"/150mm Extractor Fan c/w Timer - White | Soler_&_Palau (5210418900)

And here is the 5 inch, 180 cu.m

Silent 200 CRZ 5"/118mm Extractor Fan c/w Timer | Soler_&_Palau (5210425400)