As requested by Pungsang, Buddha states how to make a meditation room:
On that land, dig the earth and purify the place. If the house depends on heat and warmth, put a mud wall around it. The door of the meditation house should face east, north or west, but never south. If there is downstairs and upstairs, at least one door should not face south. Put a window towards the south or the east.
A dedicated meditation room is auspicious for a good retreat and helps the mind remain undisturbed, as outer and inner conditions are dependent arisings. Having a dedicated room qualifies the place as suitable for abiding in the retreat. If it is not possible to find all the conditions, at least arrange what is most comfortable for the yogi to do retreat.
The second chapter of the Guhyasamaja Tantra states that in all the directions of the earth, in places of great isolation that are adorned with flowers and fruits; in the isolation of the mountain, all realizations will be achieved.