Cove.tool refers standard ISO 13790 Annex  G.5.2 for the shading reduction factor calculation.

a) (Exterior) Blinds: Outdoor shades to limit the excessive daylight coming into the              space.
  b) (Interior) Blinds: Indoor shades to limit the excessive daylight coming into the                   space.
  c) No Blinds: No Shades for the building.

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