Fan ventilation - in or out?
 

I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

Ta.

--
JGH

Fan ventilation - in or out?
 

On Jul 28, 3:12 pm, jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

Ta.

--
JGH

Pull air out. If you pull air in it will be a concentrated patch of
cold air. If you pull air out it will be replaced through loads of
tiny drafts, and the coldness will be distributed.

A

Fan ventilation - in or out?
 

jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

Ta.

My brain immediately says 'neither' - or maybe 'both'.

If you have positive pressure that will tend to help keep dust levels
lower by pushing air out.

If you have negative pressure that will tend to draw air, and hence
dust, in.

In either case, if the pressure difference is significant, you might
find opening/closing doors and windows becomes, umm, interesting.

My brain says, have two fans, one pushing in and one sucking out -
balancing each other. If anything, a slight positive pressure.

My brain is probably broken by trying to cope with 30C. :-)

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

Fan ventilation - in or out?
 

In uk.d-i-y, jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

pedant
However you mount it, it will do both. Air will either flow in through
the fan and out through open doors, windows, and other apertures, or the
other way round.
/pedant

I think the main issue would be the outside air coming in - you'd
probably prefer not to have that concentrated near the fan. So "out"
would be the best choice.

--
Mike Barnes

Fan ventilation - in or out?
 

In article ,
Mike Barnes writes:
In uk.d-i-y, jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

pedant
However you mount it, it will do both. Air will either flow in through
the fan and out through open doors, windows, and other apertures, or the
other way round.
/pedant

I think the main issue would be the outside air coming in - you'd
probably prefer not to have that concentrated near the fan. So "out"
would be the best choice.

Probably want to exhaust the air on the upstairs side facing
the sun, and the coolest air to draw in is likely to be on
a downstairs side away from the sun or north facing.

In the summer, I replace my loft hatch with one which has a
10" vent-axia extractor fan, which serves both to extract
the hot air from upstairs, and to help cool the extremely
hot air in the attic.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Fan ventilation - in or out?
 

"Andrew Gabriel" wrote in message
...
In article ,
Mike Barnes writes:
In uk.d-i-y, jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

pedant
However you mount it, it will do both. Air will either flow in through
the fan and out through open doors, windows, and other apertures, or the
other way round.
/pedant

I think the main issue would be the outside air coming in - you'd
probably prefer not to have that concentrated near the fan. So "out"
would be the best choice.

Probably want to exhaust the air on the upstairs side facing
the sun, and the coolest air to draw in is likely to be on
a downstairs side away from the sun or north facing.

In the summer, I replace my loft hatch with one which has a
10" vent-axia extractor fan, which serves both to extract
the hot air from upstairs, and to help cool the extremely
hot air in the attic.

--
Andrew Gabriel


Let me check I have got this correct.

You have a 10" fan in the loft hatch to blow air (from the landing I
presume) into the loft. This sounds OK for my house. Did you need to make
any extra vents in the loft?

Adam

Fan ventilation - in or out?
 

In article ,
"ARWadworth" writes:

"Andrew Gabriel" wrote in message
...
In article ,
Mike Barnes writes:
In uk.d-i-y, jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

pedant
However you mount it, it will do both. Air will either flow in through
the fan and out through open doors, windows, and other apertures, or the
other way round.
/pedant

I think the main issue would be the outside air coming in - you'd
probably prefer not to have that concentrated near the fan. So "out"
would be the best choice.

Probably want to exhaust the air on the upstairs side facing
the sun, and the coolest air to draw in is likely to be on
a downstairs side away from the sun or north facing.

In the summer, I replace my loft hatch with one which has a
10" vent-axia extractor fan, which serves both to extract
the hot air from upstairs, and to help cool the extremely
hot air in the attic.

Let me check I have got this correct.

You have a 10" fan in the loft hatch to blow air (from the landing I
presume) into the loft. This sounds OK for my house. Did you need to make
any extra vents in the loft?

No - it's got vents around the soffits. It would probably
work much better with a vent at the apex, but there isn't
one and that would be hard to implemnt.

The original aim was to keep the loft cooler, and it probably
manages to knock some degrees off. It was 36C up there
today at 2pm -- it would probably have been something well
over 40C without it.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Fan ventilation - in or out?
 

"jgharston" wrote in message
...
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?



Maybe it depends on the location. An extractor fan in the hall might draw
smells out of the kitchen and loo, and damp air from the bathroom,


--
Michael Chare

Fan ventilation - in or out?
 

jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?


Definitely ;-)

Fan ventilation - in or out?
 

Andrew Gabriel wrote:
Probably want to exhaust the air on the upstairs side facing
the sun, and the coolest air to draw in is likely to be on
a downstairs side away from the sun or north facing.

That was what I was thinking of.

In the summer, I replace my loft hatch with one which has a
10" vent-axia extractor fan, which serves both to extract
the hot air from upstairs, and to help cool the extremely
hot air in the attic.

Hmm. There's an idea. My cellar is always noticable cool,
even in the heights of summer. I could do something to
draw that cold air into the rest of the house - passive
air conditioning :)

--
JGH

Fan ventilation - in or out?
 

On 29 Jul, 19:28, Owain wrote:
jgharston wrote:
Hmm. There's an idea. My cellar is always noticable cool,
even in the heights of summer. I could do something to
draw that cold air into the rest of the house - passive
air conditioning :)

Or you could just take a deckchair and portable telly down there ...

Good idea. Our cat has taken up residence in the cellar in protest at
the hot weather. Just be grateful that you haven't evolved with a
black fur coat instead of sweat glands.

Fan ventilation - in or out?
 

On 28 Jul, 16:12, jgharston wrote:
I'm planning on installing a fan to create an active
through-draft through the house. Should it be mounted
to pull air into the house or pull air out of the house?

Get a reversible one so that when you're there alone you can sit in
the cool breeze, but when the house is full of people (or smoke from
the cooking) you can spread the sucking around.

Chris

Fan ventilation - in or out?
 

In article ,
Huge writes:
On 2008-07-28, Andrew Gabriel andrew@a17 wrote:

The original aim was to keep the loft cooler,

Why?

I have some electronics up there relating to home automation.
Also, after a few weeks of hot weather, the cold water tank
becomes a warm water tank, even though it's lagged.
Also, even though well insulated, it seems to generate heat
radiated from the upstairs ceilings.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]