# How to list and measure area surfaces

I have a large model (at least for my experience) with a conditioned area of more than 180 000 m2.

I only have a thermal zone for each floor to reduce simulation time now. I want to evaluate the savings due to the new constructions I have tested in the model so I need to know the outdoor surface area to calculate the costs. Do someone know how to list the outdoor surfaces (all these surfaces has Outside boundary condition as Outdoor) and measure the area?

I found the total floor area but I couldn't find a number for the outdoor surface area. One step forward would be to list the surfaces depending on the orientation too. I would appreciate if someone could help me.

P.S.:I'm using the Legacy Open Studio plug-in to generate the base IDF.