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Insulating a metal door: curtain?


Garald

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Another chapter in the insulation saga!

 

My ground-floor doors are metal security doors. Now, metal is of course a heat conductor, and I don't know what is inside the doors. So - what to do about this?

 

My architect suggests adding fabric on the inside:

 

https://www.futura-sciences.com/maison/comparatifs/meilleur-rideau-isolant-thermique-comparatif/

 

Does that really make a difference? Is it best?

 

 

IMG-20230116-WA0001.jpg

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Follow-up question:

 

The idea does seem to make sense - after all, why not treat a metal door as a bad window you don't mind not seeing through?

 

But - does it make sense to have the back of the drape made of reflective material? Sure, it does, but: of the same kind of reflective material as an ordinary heat-insulating curtain? The heat radiated by the (dark grey) door won't be mainly in the visible-light spectrum. Should I focus mainly on having thick drapes?

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First check that the door is not insulated. Metal doors are often filled with polystyrene. There is still a lot of conduction through the edges though.

 

Fabric wont make much difference, but a heavy curtain could slow the flow of air.

 

You could face the inner side with thin insulation.

What is the context? Is that your door? It looks like a deep-freeze door.

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Well, there are curtains that claim to be made out of reflective material:

 

https://www.moondreamwebstore.fr/rideau-thermique-82

(let's call this option A)

 

It seems to hard to get any precise information about them, though (R-value?).

 

Or is any thick curtain likely to be about as good? Then I might as well get something with William-Morris patterns, so as to horrify my girlfriend. (I think that would go very well with the staircase, actually.)

 

Option B: https://www.ebay.co.uk/str/madewithlovebyjulie

Option 😄 https://society6.com/product/strawberry-thief-by-william-morris4674878_blackout-curtain?sku=s6-19490847p103a251v846a252v849

 

Is there any real reason to expect different performance from A, B and C? Which ones are more likely to make a real difference, and by how much?

 

6 hours ago, saveasteading said:

First check that the door is not insulated. Metal doors are often filled with polystyrene. There is still a lot of conduction through the edges though.

 

What is the context? Is that your door? It looks like a deep-freeze door.

No, that's not my door - that's an example photo the architect sent me. The doors I am talking about are pretty standard grey metallic safety doors. They may have some insulation inside - I can't really tell. This is a place I bought recently; I got a bunch of receipts from the previous owners for the various improvements they did, but none of them mention doors, so I assume the doors were installed by the owners before them, and there's no realistic way of getting information from those.

 

 

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That looks like an industrial door (for a warehouse). Probably made of flat steel folded to shape, with a polystyrene core.

So insulated, but with a lot of cold bridges at the circumference and some through the structure. 

Does it feel cold?

Covering the inside would be feasible but ugly.

I stick with the big curtain solution. It will isolate the room air from the door and reduce air cooling.

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4 hours ago, saveasteading said:

Does it feel cold?

 

Will check when I am back. I could ask the contractor.

 

4 hours ago, saveasteading said:

Covering the inside would be feasible but ugly.

 

Right, that's what the architect said.

 

4 hours ago, saveasteading said:

I stick with the big curtain solution. It will isolate the room air from the door and reduce air cooling.

 

So, should I go with one of the high-grade options, like https://www.moondreamwebstore.fr/rideau-thermique-82  (which are optimized for a windows or window-doors, anyhow)? Or would something like https://www.ebay.co.uk/itm/285026787569?hash=item425ceba0f1:g:qOsAAOSwh6tjZVF8

also be good?

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37 minutes ago, saveasteading said:

They look good.

For somd reason, curtains are half the price in britain. We use Dunelm Mill. So worth a look.

I did, £48. 

 

Well, British curtains are much less in the UK because Brexit!

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2 minutes ago, Garald said:

less in the UK because Brexit

No. Nothing is cheaper for that reason.

 

Curtains, bedding, timber, cheaper in uk

Tiles, Wine, cheese, branded european goods, cheaper eu.

 

Google dunelm mill thermal curtains

 

 

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Just now, saveasteading said:

No. Nothing is cheaper for that reason.

 

 

It's cheaper than in the continent (a statement that is logically equivalent to "it's more expensive than in the continent", which is what has really happened), not cheaper than before!

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my blackout curtains are basically just normal curtains with a plastic like material on the side facing the window.

id look for some thick woolly fleece type curtains. you could try getting some spare sticks of wood and hanging a duvet cover up in front of the door and see if it makes a difference. 

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9 hours ago, saveasteading said:

That looks like an industrial door (for a warehouse). Probably made of flat steel folded to shape, with a polystyrene core.

So insulated, but with a lot of cold bridges at the circumference and some through the structure. 

Does it feel cold?

 

The architect confirms: they feel cold. She also doubts they are industrial-grade, in spite of their industrial appearance.

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Could you glue some ply faced PIR on to the internal face and get your joiner to make trims to make it look good? 

 

One slight (maybe overthinking it) worry I would have is getting tangled in the curtain in a fire escape situation. 

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26 minutes ago, Iceverge said:

Could you glue some ply faced PIR on to the internal face and get your joiner to make trims to make it look good? 

 

You mean, on the inside of the door, or outside? The latter option may not be super for the pyroparanoid.

 

26 minutes ago, Iceverge said:

 

One slight (maybe overthinking it) worry I would have is getting tangled in the curtain in a fire escape situation. 

 

Hm, that's right. Otoh the curtain would hang flat against the door, and there would be no cord to get tangled in.

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Ah. Well, we haven't used PIR elsewhere, but it's not as if we were adamantly opposed to it (though we made a consistent choice not to use rockwool, other than in the roof, which will get raised at some point in the undefined future). I'll talk to the contractor - this seems to be the sort of thing he knows well.

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