Airplane insulation

Hi guys

We are doing a physics project in school concerning the thermodynamics
of flight and I have some questions I was hoping you could help me
with.

I need to estimate how much heat is lost from the cabin to the outside
when flying at 10000m. I have calculated the approximate outside
temperature given the sea-level temperature but I don't know how planes
are insulated!
It is my impression that the hull is typically made of an exterior
aluminum skeleton followed by the insulation and finally the inner
cabin wall. In this setup the main insulation effect will probably come
from the insulating material.
I expect the insulation to be at least as good as the ones used in
modern buildings but I don't know how much of it is used - can you give
me some examples of the width of the insulation please?

Thank you in advance.

Best regards
Andreas