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klkbloke August 27th 06 02:37 PM

Extractor fan in bathroom.
 
Hi All,
I've just moved to a house with a downstairs bathroom hence leaving a
window open after a shower is no longer an option. I thought the best
option would be to install an extractor fan while I'm putting in the
new bathroom suite. However I have two questions...

1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. The question is, do
I need to install a duct through the wall and a vent on the exterior
wall? Or can I just install the fan on the interior wall only? I would
prefer not to touch the outside of the house as the cast iron "brick"
is quite ornate (and 80+ years old) and fits in with the rest of the
house. Would I risk damp getting into the cavity? I'd assume I would be
no better or worse than the current arrangement?

Cheers.


Mary Fisher August 27th 06 02:43 PM

Extractor fan in bathroom.
 

"klkbloke" wrote in message
oups.com...
Hi All,
I've just moved to a house with a downstairs bathroom hence leaving a
window open after a shower is no longer an option. I thought the best
option would be to install an extractor fan while I'm putting in the
new bathroom suite. However I have two questions...

1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.

Ours is excellent, I can't recommend them highly enough. It's magic when you
hear the (very low) noise come on when you're in the bath. Under the shower
I never hear it at all.

Mary



john2 August 27th 06 02:55 PM

Extractor fan in bathroom.
 
g at one for ~£30 from Screwfix.

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. The question is, do
I need to install a duct through the wall and a vent on the exterior
wall? Or can I just install the fan on the interior wall only? I would
prefer not to touch the outside of the house as the cast iron "brick"
is quite ornate (and 80+ years old) and fits in with the rest of the
house.


There should be a air-pressure operated flap installed on the outside to
prevent wind blowing in when the fan is off, otherwise the bathroom will
be permanently cold. Doesn't the air brick vent the void between the
floors.

john2


John White August 27th 06 03:20 PM

Extractor fan in bathroom.
 
klkbloke wrote:

I've just moved to a house with a downstairs bathroom hence leaving a
window open after a shower is no longer an option. I thought the best
option would be to install an extractor fan while I'm putting in the
new bathroom suite. However I have two questions...


1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.


I've put in a few of these recently and would strongly recommend them.
They have the great advantage of only switching on when they are
needed.

Use can a double pole switch as an isolator, and wire it straight into
the lighting circuit.

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. The question is, do
I need to install a duct through the wall and a vent on the exterior
wall? Or can I just install the fan on the interior wall only? I would
prefer not to touch the outside of the house as the cast iron "brick"
is quite ornate (and 80+ years old) and fits in with the rest of the
house. Would I risk damp getting into the cavity? I'd assume I would be
no better or worse than the current arrangement?


I would put a new flue through the wall away from the cast iron grill,
and then leave the grill to ventilate the cavity.

John
--
John White,
Electrical Contractor

John White August 27th 06 03:34 PM

Extractor fan in bathroom.
 
Huge wrote:

On 2006-08-27, john2 wrote:


There should be a air-pressure operated flap installed on the outside to
prevent wind blowing in when the fan is off, otherwise the bathroom will
be permanently cold.


IME these are completely useless, and on windy days a freezing draught
will howl through the fan. Get one with positive operation on the
shutters.


That's my experience as well. They also make a terrible racket on
windy days.

Much better to get a fan with integral shutters and have a plain vent
on the outside.

John
--
John White,
Electrical Contractor

Weatherlawyer August 27th 06 03:37 PM

Extractor fan in bathroom.
 

John White wrote:
klkbloke wrote:

I've just moved to a house with a downstairs bathroom hence leaving a
window open after a shower is no longer an option. I thought the best
option would be to install an extractor fan while I'm putting in the
new bathroom suite. However I have two questions...


1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.


I've put in a few of these recently and would strongly recommend them.
They have the great advantage of only switching on when they are
needed.

Use can a double pole switch as an isolator, and wire it straight into
the lighting circuit.

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. The question is, do
I need to install a duct through the wall and a vent on the exterior
wall? Or can I just install the fan on the interior wall only? I would
prefer not to touch the outside of the house as the cast iron "brick"
is quite ornate (and 80+ years old) and fits in with the rest of the
house. Would I risk damp getting into the cavity? I'd assume I would be
no better or worse than the current arrangement?


I would put a new flue through the wall away from the cast iron grill,
and then leave the grill to ventilate the cavity.


I doubt he has a cavity. Old housing had little plumbing, lots of
chimneys and few security worries, so they could rely on natural
ventilation to air them. The vent in a must have for old property.

I'd hire a core drill and bore a new hole for the fan somewhere where
the new feature would be hidden outside, if that was possible.


John Rumm August 27th 06 04:18 PM

Extractor fan in bathroom.
 
klkbloke wrote:

1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.


Yup, I have fitted a couple of the 4" ones. They seem to do what it says
on the tin. You get in the shower - after a few mins the fan kicks in.
It then runs for 30mins to an hour after until the room is dry again.
You can tweek the sensitivity with a knob on the underside (you may need
to do this from time to time if the weather changes dramatically)

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. The question is, do
I need to install a duct through the wall and a vent on the exterior
wall? Or can I just install the fan on the interior wall only? I would
prefer not to touch the outside of the house as the cast iron "brick"
is quite ornate (and 80+ years old) and fits in with the rest of the
house. Would I risk damp getting into the cavity? I'd assume I would be
no better or worse than the current arrangement?


As you suggest, if you don't line it then you will fill the cavity with
water. You can get rectangular ducting (TLC stock it), and a short
length ought to do it if you make sure it is sealed to the wall on the
inside and goes through as far as the cast iron on the far side.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm August 27th 06 04:22 PM

Extractor fan in bathroom.
 
John White wrote:

I've put in a few of these recently and would strongly recommend them.
They have the great advantage of only switching on when they are
needed.

Use can a double pole switch as an isolator, and wire it straight into
the lighting circuit.


IIRC, the ones I fitted required fusing at 3A which meant I needed a FCU
as well...

I would put a new flue through the wall away from the cast iron grill,
and then leave the grill to ventilate the cavity.


This air brick sounds more like the type that we have in our bathroom -
it is simply connected through the wall to a louvered vent on the inside
and serves as permenent room ventilation.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John White August 27th 06 04:42 PM

Extractor fan in bathroom.
 
John Rumm wrote:

John White wrote:

I've put in a few of these recently and would strongly recommend them.
They have the great advantage of only switching on when they are
needed.

Use can a double pole switch as an isolator, and wire it straight into
the lighting circuit.


IIRC, the ones I fitted required fusing at 3A which meant I needed a FCU
as well...


Quite right. I meant to say "Use a double pole, switched FCU as an
isolator, and ...".

I really should read what I write before I post it. :-(

I would put a new flue through the wall away from the cast iron grill,
and then leave the grill to ventilate the cavity.


This air brick sounds more like the type that we have in our bathroom -
it is simply connected through the wall to a louvered vent on the inside
and serves as permenent room ventilation.


Fair enough. I was going by the OP's reference to a cavity.

John
--
John White,
Electrical Contractor

klkbloke August 27th 06 05:52 PM

Extractor fan in bathroom.
 

John White wrote:

John Rumm wrote:

John White wrote:

I've put in a few of these recently and would strongly recommend them.
They have the great advantage of only switching on when they are
needed.

Use can a double pole switch as an isolator, and wire it straight into
the lighting circuit.


IIRC, the ones I fitted required fusing at 3A which meant I needed a FCU
as well...


Quite right. I meant to say "Use a double pole, switched FCU as an
isolator, and ...".

I really should read what I write before I post it. :-(

I would put a new flue through the wall away from the cast iron grill,
and then leave the grill to ventilate the cavity.


This air brick sounds more like the type that we have in our bathroom -
it is simply connected through the wall to a louvered vent on the inside
and serves as permenent room ventilation.


Fair enough. I was going by the OP's reference to a cavity.

John
--
John White,
Electrical Contractor


Hi All,

Thanks for the many responses. I'll try and answer the various points
raised.

- it is a cavity wall (I checked before I bought the house).
- the fan is rated at 15w so connecting it to the lighting circuit
(using a dp switch) is ok (AFAIK).

Basically there is a cast iron grill on the inside wall and one on the
outside wall. My plan as it stands (unless someone persuades me any
differently) is to install the fan on the inside and duct it to the
outside grill so as not to encourage the damp into the cavity.

This would still leave a 3" X 5" area of the grill unobstructed by the
fan.

I'm reluctant to put another whole through the wall as it feels a
little ott. At present most of the ventilation to the bathroom is via
this grill which is currently open to the cavity.

What do you think?


Mary Fisher August 27th 06 09:18 PM

Extractor fan in bathroom.
 

"klkbloke" wrote in message
oups.com...

John White wrote:

John Rumm wrote:

John White wrote:

I've put in a few of these recently and would strongly recommend them.
They have the great advantage of only switching on when they are
needed.

Use can a double pole switch as an isolator, and wire it straight into
the lighting circuit.

IIRC, the ones I fitted required fusing at 3A which meant I needed a FCU
as well...


Quite right. I meant to say "Use a double pole, switched FCU as an
isolator, and ...".

I really should read what I write before I post it. :-(

I would put a new flue through the wall away from the cast iron grill,
and then leave the grill to ventilate the cavity.

This air brick sounds more like the type that we have in our bathroom -
it is simply connected through the wall to a louvered vent on the inside
and serves as permenent room ventilation.


Fair enough. I was going by the OP's reference to a cavity.

John
--
John White,
Electrical Contractor


Hi All,

Thanks for the many responses. I'll try and answer the various points
raised.

- it is a cavity wall (I checked before I bought the house).
- the fan is rated at 15w so connecting it to the lighting circuit
(using a dp switch) is ok (AFAIK).

Basically there is a cast iron grill on the inside wall and one on the
outside wall. My plan as it stands (unless someone persuades me any
differently) is to install the fan on the inside and duct it to the
outside grill so as not to encourage the damp into the cavity.

This would still leave a 3" X 5" area of the grill unobstructed by the
fan.

Spouse made a wooden panel on which to mount the fan which would close off
the exposed grill and painted it to match the wall. There is ducting through
the cavity of course.

Mary



[email protected] August 27th 06 10:13 PM

Extractor fan in bathroom.
 
klkbloke wrote:

Hi All,
I've just moved to a house with a downstairs bathroom hence leaving a
window open after a shower is no longer an option. I thought the best
option would be to install an extractor fan while I'm putting in the
new bathroom suite. However I have two questions...

1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. The question is, do
I need to install a duct through the wall and a vent on the exterior
wall? Or can I just install the fan on the interior wall only? I would
prefer not to touch the outside of the house as the cast iron "brick"
is quite ornate (and 80+ years old) and fits in with the rest of the
house. Would I risk damp getting into the cavity? I'd assume I would be
no better or worse than the current arrangement?

Cheers.


Partially blocking these vents is not a good idea.

small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.

Th real solution is to add a lock to the window that enables it to be
locked quarter to half an inch ajar, so no-one can see in but some
ventilation occurs.

Compared to a fan:
cheaper to buy
cheaper to install
no run cost
silent
much longer lived and more reliable
more pleasant in use.


NT


chris French August 28th 06 10:22 AM

Extractor fan in bathroom.
 
In message . com,
writes
klkbloke wrote:

Hi All,
I've just moved to a house with a downstairs bathroom hence leaving a
window open after a shower is no longer an option. I thought the best
option would be to install an extractor fan while I'm putting in the
new bathroom suite. However I have two questions...

1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. T


Partially blocking these vents is not a good idea.

We had a similar arrangement in our old house, the internal airbrick was
covered over in the renovations, never caused a problem.

small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.

not my experience at all. Had a 100mm inline van in the loft, venting
the bathroom through the roof. operated by a humidistat. It worked very
well, much better than the previous arrangement - a window. Never any
problems with damp, mould etc.

--
Chris French


nafuk August 28th 06 11:44 AM

Extractor fan in bathroom.
 
Hi, I need a fan also. Can anyone recommend one with a "positive
closure" vent please.
Thank you

chris French wrote:
In message . com,
writes
klkbloke wrote:

Hi All,
I've just moved to a house with a downstairs bathroom hence leaving a
window open after a shower is no longer an option. I thought the best
option would be to install an extractor fan while I'm putting in the
new bathroom suite. However I have two questions...

1) I've seen a fan which operates on a humidistat, not connected to the
light switch in anyway. Has anyone had experience of these? Are they
any good. I'm looking at one for ~£30 from Screwfix.

2) I have an airbrick - well it's actually cast iron. I was planning to
knock that through and use that to install the fan. T


Partially blocking these vents is not a good idea.

We had a similar arrangement in our old house, the internal airbrick was
covered over in the renovations, never caused a problem.

small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.

not my experience at all. Had a 100mm inline van in the loft, venting
the bathroom through the roof. operated by a humidistat. It worked very
well, much better than the previous arrangement - a window. Never any
problems with damp, mould etc.

--
Chris French



[email protected] August 28th 06 11:58 AM

Extractor fan in bathroom.
 
chris French wrote:
In message . com,
writes
klkbloke wrote:


Partially blocking these vents is not a good idea.


We had a similar arrangement in our old house, the internal airbrick was
covered over in the renovations, never caused a problem.


sometimes it does, sometimes it doesnt, doesnt make it a good idea.


small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.


not my experience at all. Had a 100mm inline van in the loft, venting
the bathroom through the roof. operated by a humidistat. It worked very
well, much better than the previous arrangement - a window. Never any
problems with damp, mould etc.


I wonder why. My 6 inch one was useless.


NT


Guy King August 28th 06 12:29 PM

Extractor fan in bathroom.
 
The message
from chris French contains these words:

Had a 100mm inline van in the loft,


These new tiny Transits are quite versatile, aren't they?

--
Skipweasel
Pay no attention to that man behind the curtain.

Mary Fisher August 28th 06 12:43 PM

Extractor fan in bathroom.
 

"Guy King" wrote in message
...
The message
from chris French contains these
words:

Had a 100mm inline van in the loft,


These new tiny Transits are quite versatile, aren't they?


I saw a couple last weekend but our loft hatch wouldn't take one.

Mary

--
Skipweasel
Pay no attention to that man behind the curtain.




Alan Holmes August 28th 06 01:17 PM

Extractor fan in bathroom.
 

"John White" wrote in message
...

I really should read what I write before I post it. :-(


Join the club, hands up anyone who has read anything before they have
pressed the 'send' button!

Alan



John Rumm August 28th 06 03:21 PM

Extractor fan in bathroom.
 
wrote:

small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.

Th real solution is to add a lock to the window that enables it to be
locked quarter to half an inch ajar, so no-one can see in but some
ventilation occurs.

Compared to a fan:
cheaper to buy
cheaper to install
no run cost
silent
much longer lived and more reliable
more pleasant in use.


In our experiance the window solution never really worked. The bathroom
has one permenant vent like the OPs, plus a large fanlight window that
is always open (although partially obscured by the window blind). If you
had a shower the condensation would still hang about for ages.

After switching to mains pressure hot water that made the situation even
worse and a fan became a requirement. The small 4" fan actually does far
better than I expected.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd -
http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

ARWadsworth August 28th 06 06:31 PM

Extractor fan in bathroom.
 

wrote in message
ups.com...
chris French wrote:
In message . com,
writes
klkbloke wrote:


Partially blocking these vents is not a good idea.


We had a similar arrangement in our old house, the internal airbrick was
covered over in the renovations, never caused a problem.


sometimes it does, sometimes it doesnt, doesnt make it a good idea.


small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.


not my experience at all. Had a 100mm inline van in the loft, venting
the bathroom through the roof. operated by a humidistat. It worked very
well, much better than the previous arrangement - a window. Never any
problems with damp, mould etc.


I wonder why. My 6 inch one was useless.


You need to let air in. A gap under the bathroom door is one way. I remember
one regular poster a few years ago mentioning the plasterboard on a stud
wall being pulled down due to a lack of air entering a room and the fan
creating a vacuum.

Adam



chris French August 28th 06 11:26 PM

Extractor fan in bathroom.
 
In message . com,
writes
chris French wrote:
In message . com,
writes
klkbloke wrote:


Partially blocking these vents is not a good idea.


We had a similar arrangement in our old house, the internal airbrick was
covered over in the renovations, never caused a problem.


sometimes it does, sometimes it doesnt, doesnt make it a good idea.



Well I think it means you should think about it before doing it

The went is this case would have ended up on the shower wall which
wasn't really welcome. It presumably was to provide some fixed
ventilation into the bathroom or WC - can't remember - we knocked them
together.

The fan was going to provide suitable ventilation to the room, and the
outside vent was still left in place. Though the house had other air
bricks to provide ventilation of the cavity
--
Chris French


David Hansen August 29th 06 07:20 AM

Extractor fan in bathroom.
 
On 27 Aug 2006 14:13:36 -0700 someone who may be
wrote this:-

small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.


Along with others, I disagree. A small in-line fan which extracts
directly above the bath does a good job of removing much of the
steam all year round. Replacement air comes from diagonally
opposite.

When out of the bath there is usually little point burning
electricity to remove the last of the humidity, that is what the
window opens for.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

nightjar August 29th 06 08:20 AM

Extractor fan in bathroom.
 

wrote in message
ups.com...
chris French wrote:
In message . com,

.....
not my experience at all. Had a 100mm inline van in the loft, venting
the bathroom through the roof. operated by a humidistat. It worked very
well, much better than the previous arrangement - a window. Never any
problems with damp, mould etc.


I wonder why. My 6 inch one was useless.


Quite probably due to an inadequate supply of air into the room. My
humidistat operated fan works fine, but I ought to get around to fitting a
door on the bathroom some time.

Colin Bignell



Mary Fisher August 29th 06 09:13 AM

Extractor fan in bathroom.
 

"David Hansen" wrote in message
...
On 27 Aug 2006 14:13:36 -0700 someone who may be
wrote this:-

small bathroom fans are really hopeless anyway, and not even worth
switching on at bathtime.


Along with others, I disagree. A small in-line fan which extracts
directly above the bath does a good job of removing much of the
steam all year round. Replacement air comes from diagonally
opposite.


Ours is fitted in the wall vent which isn't near the bath but over the sink.
The humidistat itself, however, is close to the bath - isn't that more
important?

When out of the bath there is usually little point burning
electricity to remove the last of the humidity, that is what the
window opens for.


Ours doesn't but the door does and is usually open - except when I'm in the
bath :-)

There's some humidity in all air in the house though if only from breathing,
that doesn't mean it's damp.

Mary



nightjar August 29th 06 11:59 PM

Extractor fan in bathroom.
 

"Alan Holmes" wrote in message
...

"John White" wrote in message
...

I really should read what I write before I post it. :-(


Join the club, hands up anyone who has read anything before they have
pressed the 'send' button!


It takes training to read what you have actually written, instead of what
you thought you had written.

Colin Bignell



Mary Fisher August 30th 06 10:35 AM

Extractor fan in bathroom.
 

"nightjar .uk.com" nightjar@insert my surname here wrote in message
...

"Alan Holmes" wrote in message
...

"John White" wrote in message
...

I really should read what I write before I post it. :-(


Join the club, hands up anyone who has read anything before they have
pressed the 'send' button!


It takes training to read what you have actually written, instead of what
you thought you had written.

Colin Bignell


Who does that kind of training?

Mary






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