It is a mitzva to designate a permanent place for prayer. This is what the patriarch Avraham did, as it is written: “Avraham woke up early in the morning [to go] to the place where he had stood (amad) before God” (Bereishit 19:27), implying that he had a regular place where he would stand before God. The primary importance of establishing a place to pray pertains to the recitation of the Amida (lit. “standing”) prayer (Ben Ish Ĥai, Miketz 4).
The designation of a place of prayer expresses the complete connection that we have with God. Everything else in the world can change, but one’s connection to God is the most permanent and stable reality and should therefore transpire at a fixed place. The Sages say: “Whoever sets a place to pray is helped by the God of Avraham, and his enemies fall to him” (Berakhot 6b, 7b; see Maharal, Netiv Ha-avoda, ch. 4).
Men fulfill this mitzva by establishing a set place to pray in the synagogue (SA 90:19). Women fulfill it by establishing a permanent place to pray at home, a place where she tries to pray constantly. A woman whose house bustles with people or children should set a place to pray in a secluded corner, so that her concentration is not disrupted (see SA 90:20).
One must pray in a room with a window, and le-khatĥila it is good that a window opens toward Jerusalem, so that if her kavana is disrupted, she can look up towards the heavens (SA 90:4; MB 90:8). However, one should not establish her place of prayer next to a window with a view of the public domain, for whatever is happening on the street is likely to disturb her prayer (SA 90:20).
If she is in a place with no windows, she should pray in a well-lit place, since some poskim explain that the reason for praying in a room with windows is because the light that comes in settles the thoughts of the person praying (Talmidei Rabbeinu Yona); therefore, good lighting can be considered a substitute for a window.