Improve the insulation of windows: blinds, curtains, blinds?

[Christophe]

That's all in the title: what is the most econological solution to improve insulation (night) windows / existing chassis?

Obviously, we think all the additions shutters (rolling), but:
a) it is expensive anyway! Is only rentabilisable their lifetime?
b) is frankly quite ugly when it's not original (ca exceed)
c) ca not isolated as this (see below).
d) impossible in some cases!

So here what are the cheaper alternatives and can be as effective?

I see 2 for now:

a) thick curtains (you know like in the strong castle! ), the wall hanging pros also offer "thermal lining".

b) for the glazing only: blinds on those style skylight (not beautiful but good)

So here: how to estimate the thermal resistance of a thick curtain?

Safety shutters

a) Safety shutters characterized by an additional thermal resistance provided by all air-blade shutter ventilated: R> 0,20 m² ° C / W.

For a single component with foam polyurethane thermal transmittance of 0.035, this corresponds to an insulation thickness of the component at least: 0,2 0.035 * = = 0.007 7 mm.

Nature of the closures (shutters, blinds) is also involved in reducing losses, especially at night.

A good modern frame has an overall K of 1.1 therefore a thermal resistance of 1 / 1.1 = 0.91 m² ° C / W, it "good shutter" therefore only provides 0.2 - 0.3 so about 20-30% gain ...

ps: my question is not innocent, in the Ardennes, there are few houses with roller shutters, that had "surprised" us enough when we arrived in the region. Our house doesn't have one either (but we have big curtains).

[dirk pitt]

Christopher, I think you're forgetting something important in insulation made from components (whether moving or flaps or other), it is air blade creates between the flap and the window
This air gap which can be ten cm thick does not move too much if the shutter is "relatively" tight and without having made any calculations, it contributes greatly to the insulation in my opinion.

anecdote: I was this weekend in an old house in Chamonix and there were very old windows with double glazing but simply 4mm about air 10cm between the two windows. in + there were wooden shutters.

[Christophe]

Well ... yes, but:

a) 10 cm air is no longer an insulation: convection cancels everything ... and the double windows you mention is certainly better than single glazing but it is not a good double glazing!

b) the "standard" says:

"brought by the whole shutter-ventilated air space"

So I presume that this space which you do ALUSION is included!

In addition, it is the same (see more) with the curtains! They are rarely "stuck" to the frame!

In short we advance but still have to dig a little!

[Xian]

The double curtain seems to have real insulating virtues.

we have a large bay window in the living room, 3mx2, the "shutter" of which is a heavy barn door that we no longer close. we use the double curtain.

I would have put two thermometers on either side of the curtain to confirm my impression. The temperature of this piece is very stable indeed, even in cold weather

Note that we have underfloor heating

[dirk pitt]

Well ... yes, but:

a) 10 cm air is no longer an insulation: convection cancels all ...

What convection?
unless there are days 3 cm at the bottom and top.
the air is almost motionless in this area

put a thermometer in the space between the door and the window and compares the value to the outdoor temperature an early winter morning.
You'll see if the air is not insulating.

[Christophe]

Xian: we have exactly the same situation and we have just ordered "thick" curtains (we already had some but lighter ones). So in winter we will have 2 rows of curtains! It's still not cheap but it's much lighter than a roller shutter!

What convection?
unless there are days 3 cm at the bottom and top.
the air is almost motionless in this area

???? Motionless??? Frankly on 10 cm ca surprise me !!

I speak of natural convection (present any gas heat exchanges) which cancels any insulating capacity of an air knife at Beyond 2-3 cm thick ... it's not for nothing that the windows are 16 mm between glass: it is the best compromise!

If 10 cm air isolated properly: pkoi put insulation in homes that have wood osature wall around 10 cm between wall? Also: no need of insulation in the attic, simple forms would suffice! Nope they not enough!

So not 10 cm air ca not isolated WELL ... and less than 2 cm in all cases!

But good space between glass pane and is generally less than 10cm. I would have to tailor our bay window with integrated shutter want! I think it is in the 5 4 cm see ...

put a thermometer in the space between the door and the window and compares the value to the outdoor temperature an early winter morning.
You'll see if the air is not insulating.

I no doubt that it is warmer outside than in this space but it does not mean that it is well insulated!

It should indicate what in your opinion? practical example?

What would be more interesting is to measure what is the difference between T ° UP (lintel) and BAS (threshold) of the air layer-glass pane. So homogeneous: because you ca insulates well, otherwise there is the natural convection and thus losses

[Aumicron]

put a thermometer in the space between the door and the window and compares the value to the outdoor temperature an early winter morning.
You'll see if the air is not insulation

Unless I am mistaken, if the temperature at this point is higher than outside, thanks to the insulation component and not to that of air.

[dirk pitt]

If 10 cm air isolated properly: pkoi put insulation in homes that have wood osature wall around 10 cm between wall? Also: no need of insulation in the attic, simple forms would suffice! Nope they not enough!

do not mix everything.
when you can do better than 10 cm air, we do it.
between the flap and the window, the ten cm of air isolate a condition that leaks are not too important
when was whether they insulate better than 2cm or less, I will look for better but it's not obvious to put in evidence (a waterproofing surfaces of equal and equal exchange)
convection is a function of the surface in contact with the gas and the flow rate (all things being equal)
for homogeneity of high-low temperature, there may be even without stratification exchanges so it not prove anything.

[aerialcastor]

Well I searched in vain for the document but I not found. It was on this site http://www.nrc-cnrc.gc.ca/fra/idp/irc.html

The conclusion was basically that the thermal resistance of an air layer does not vary linearly and that the optimum thickness was qq cm (3 memory). In between 0 3cm and increases the thermal resistance of 3à 8cm it decreases slightly, and from 8cm it fall.

[Christophe]

Ah thank you for confirmation and clarification Castor