I always shield my Phals with our sheer curtain especially during our summers here. My Phals are also by a west facing window on a pole stand, glass is tinted a bit, gets dappled shade from the city trees as well, so it is like the wall by your window. My Phals are in bloom right now, so the flowers still need some light, so sheer curtains allows light to pass through. But west facing sun is so hot in my very dry area, so I have to shield it, and I let the ceiling fan run, especially on very hot day that we have like now. Our temps outdoors are hitting very high right now 95F and higher, so that heat is just so intense as it passes through the glass window.
But you may have much better temperature conditions than mine.
But light always gets hotter as it goes through the window, so a little protection will help, especially Phal leaves, they can burn easily.
