I also grow Phals. I actually keep it drier but in cool conditions indoors by our west facing window. I always think of it as a cool temperature growing orchid. During our hot and dry summer, it seems not to mind being dry longer, as long as I have our ceiling fan running from time to time. It loves the cool air around it, more than making it too wet. But I do water thoroughly the root zone once a week during summer. I also observe after winter, whether it made blooms or not, it seems to go on a dormant phase, not doing anything, best to keep it dry then. Once I see new roots and leaves forming, then I know it is back in business and ready again for my watering regimen. I have left these plants for over a month when I am out of the country, and they don't suffer much, I guess it was during late winter to early Spring, during its rest mode.
Though my Phals are by a west facing window and north facing sliding doors, the window is tinted, and we get good shade from city trees. When our outside temps are hovering in the triple digit mark and higher, I also draw our sheer white curtains to further cool the area. Works well so far. I also try to avoid wetting the leaves, just the root zone. Less fungal or bacterial issues that way.
I got good root growth from my Phals, and they just ramble around, outside their containers, showing me it wants to feel more air and some good light. In some ways, it reminds me of growing them like Cattleya, grow them drier, the difference is the light, Cattleya needs more light, but Phals are okay with less light or dappled light.
