Insulating a metal door: curtain?

[Garald]

56 minutes ago, saveasteading said:

If that door is new, then there will be a spec for it, including insulation. It might be better than nyou think. 

What freezing part of the world is it, very approximately?

 

Just outside Paris. The door was installed either by the previous owners or (more likely) the ones before them. I will ask.

 

 

[Adsibob]

6 hours ago, Adsibob said:

I have a pair of Dunelm curtains, I think they are similar to these... need to check. If so, they are fine as a draft barrier, but not really thick in the sense of any insulation.

 

 

Okay, I checked. They are “thermal and blackout”. On the side facing the room they are a polyester material. On the side facing the window, a plastic feeling material. They are definitely filled with something, but it’s incredibly thin. Touching the curtains, they do feel colder on the outside than on the inside, so I guess they must be doing something, but they are so thin it’s hard to believe it.

[saveasteading]

10 hours ago, Adsibob said:

they are so thin it’s hard to believe it.

It is more the barrier to air flow that is important. The thermal break from a curtain is like a thin jumper....which keeps us warm by both processes.

Will a thick curtain be better? Yes. How much? Don't know, but not a lot.

The curtain needs to touch the floor or you will get convection...downwards and cold.

I've just realised that old fashioned pelmets were not just for show, but reduced convection.

[Garald]

What sort of material should I ask to be put inside the lining? 

[saveasteading]

7 hours ago, Garald said:

What sort of material should I ask to be put inside the lining? 

Anything that stops air flowing through the curtain.