Venetian blinds - angled up or down?
 

Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele

Venetian blinds - angled up or down?
 

On 01/07/2019 15:08, D.M. Procida wrote:
Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele


What are they made of?

We have metal ones and they radiate so I have them angled down so
there's less surface area catching the sun.

Venetian blinds - angled up or down?
 

I've never noticed any appreciable difference. There are too many gaps at
the sides and too much turblurance generally. Use an outdoor shade.
Brian

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"D.M. Procida" wrote in
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Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele

Venetian blinds - angled up or down?
 

On 01/07/2019 16:33, Chris Hogg wrote:
On Mon, 1 Jul 2019 16:08:47 +0200,
(D.M. Procida) wrote:

Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele

I very much doubt it makes any difference. With all blinds, the _best_
arrangement is to have them _outside_ the window, but of course that's
not often practicable. That way the sunshine, i.e. the infra-red
component, never gets into the room/conservatory/greenhouse/whatever,
so the inside doesn't get warmed too much. Once the sunlight has come
through the glass, the best you can hope for is to reflect a portion
of it back out again, which means having the slats angled so that the
flat surfaces face the sun, i.e. upwards by your description. In terms
of trapping the warm air between the window and the blind, the warm
air will find its way out into the room somehow whichever way you have
them.

I have worked in offices that have them *between* the panes of the
double glazing. Stops them getting dirty or damaged.

SteveW

Venetian blinds - angled up or down?
 

On Mon, 1 Jul 2019 20:29:37 +0100, Steve Walker
wrote:

On 01/07/2019 16:33, Chris Hogg wrote:
On Mon, 1 Jul 2019 16:08:47 +0200,
(D.M. Procida) wrote:

Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele

I very much doubt it makes any difference. With all blinds, the _best_
arrangement is to have them _outside_ the window, but of course that's
not often practicable. That way the sunshine, i.e. the infra-red
component, never gets into the room/conservatory/greenhouse/whatever,
so the inside doesn't get warmed too much. Once the sunlight has come
through the glass, the best you can hope for is to reflect a portion
of it back out again, which means having the slats angled so that the
flat surfaces face the sun, i.e. upwards by your description. In terms
of trapping the warm air between the window and the blind, the warm
air will find its way out into the room somehow whichever way you have
them.

I have worked in offices that have them *between* the panes of the
double glazing. Stops them getting dirty or damaged.

How do you operate them? Are they motorised?

Venetian blinds - angled up or down?
 

On 01/07/2019 21:25, Scott wrote:
On Mon, 1 Jul 2019 20:29:37 +0100, Steve Walker
wrote:

On 01/07/2019 16:33, Chris Hogg wrote:
On Mon, 1 Jul 2019 16:08:47 +0200,
(D.M. Procida) wrote:

Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele

I very much doubt it makes any difference. With all blinds, the _best_
arrangement is to have them _outside_ the window, but of course that's
not often practicable. That way the sunshine, i.e. the infra-red
component, never gets into the room/conservatory/greenhouse/whatever,
so the inside doesn't get warmed too much. Once the sunlight has come
through the glass, the best you can hope for is to reflect a portion
of it back out again, which means having the slats angled so that the
flat surfaces face the sun, i.e. upwards by your description. In terms
of trapping the warm air between the window and the blind, the warm
air will find its way out into the room somehow whichever way you have
them.

I have worked in offices that have them *between* the panes of the
double glazing. Stops them getting dirty or damaged.

How do you operate them? Are they motorised?

No the units are not sealed. It was a few years ago and I can't remember
exactly, but I am pretty sure that raise and lower was by a winding
handle on a shaft passing into the frame, I'm just not sure whether tilt
was similar or used a cord passing through.

SteveW

Venetian blinds - angled up or down?
 

On Monday, July 1, 2019 at 9:52:15 PM UTC+1, Steve Walker wrote:
On 01/07/2019 21:25, Scott wrote:
On Mon, 1 Jul 2019 20:29:37 +0100, Steve Walker
wrote:

On 01/07/2019 16:33, Chris Hogg wrote:
On Mon, 1 Jul 2019 16:08:47 +0200,
(D.M. Procida) wrote:

Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele

I very much doubt it makes any difference. With all blinds, the _best_
arrangement is to have them _outside_ the window, but of course that's
not often practicable. That way the sunshine, i.e. the infra-red
component, never gets into the room/conservatory/greenhouse/whatever,
so the inside doesn't get warmed too much. Once the sunlight has come
through the glass, the best you can hope for is to reflect a portion
of it back out again, which means having the slats angled so that the
flat surfaces face the sun, i.e. upwards by your description. In terms
of trapping the warm air between the window and the blind, the warm
air will find its way out into the room somehow whichever way you have
them.

I have worked in offices that have them *between* the panes of the
double glazing. Stops them getting dirty or damaged.

How do you operate them? Are they motorised?

No the units are not sealed. It was a few years ago and I can't remember
exactly, but I am pretty sure that raise and lower was by a winding
handle on a shaft passing into the frame, I'm just not sure whether tilt
was similar or used a cord passing through.

SteveW

You can get them inside sealed double glazed units. The ones I saw were operated by a magnetic arrangement. I did think if they got tangled in some way you would be stuck.

Simon.

Venetian blinds - angled up or down?
 

On 02/07/2019 09:03, sm_jamieson wrote:
On Monday, July 1, 2019 at 9:52:15 PM UTC+1, Steve Walker wrote:
On 01/07/2019 21:25, Scott wrote:
On Mon, 1 Jul 2019 20:29:37 +0100, Steve Walker
wrote:

On 01/07/2019 16:33, Chris Hogg wrote:
On Mon, 1 Jul 2019 16:08:47 +0200,
(D.M. Procida) wrote:

Which way is it more efficient to angle the slats of venetian blinds to
keep a room cool:

* downwards, so that warm air behind them stays there instead of being
drawn into the room (but sunlight streams through into the room)
* upwards, so that they block direct sunlight (but warm air behind them
rises upwards into the room)?

My bet is on upwards.

Daniele

I very much doubt it makes any difference. With all blinds, the _best_
arrangement is to have them _outside_ the window, but of course that's
not often practicable. That way the sunshine, i.e. the infra-red
component, never gets into the room/conservatory/greenhouse/whatever,
so the inside doesn't get warmed too much. Once the sunlight has come
through the glass, the best you can hope for is to reflect a portion
of it back out again, which means having the slats angled so that the
flat surfaces face the sun, i.e. upwards by your description. In terms
of trapping the warm air between the window and the blind, the warm
air will find its way out into the room somehow whichever way you have
them.

I have worked in offices that have them *between* the panes of the
double glazing. Stops them getting dirty or damaged.

How do you operate them? Are they motorised?

No the units are not sealed. It was a few years ago and I can't remember
exactly, but I am pretty sure that raise and lower was by a winding
handle on a shaft passing into the frame, I'm just not sure whether tilt
was similar or used a cord passing through.

SteveW

You can get them inside sealed double glazed units. The ones I saw were operated by a magnetic arrangement. I did think if they got tangled in some way you would be stuck.

As it happens, I moved into a different building for work on Monday
morning and today I noticed that the meeting rooms have their blinds
between the panes. In this case there is a knob on each frame, which
tilts the slats, but there is no mechanism for raising or lowering them.

With tilting only, there is probably little chance of them getting tangled.

SteveW