Browning but firm leaves

[swcheng15]

Hi! I'm new to this board.

I've had these orchids for years. Only this year have I noticed that they're not happy. They are in a south facing garden window but is slightly shaded with paper on the top shelf. I live in northern california where we've had some cold weather. Also, as an aside, our house heater hasn't worked all winter long, so the house is colder (maybe low to mid 60s). Any way, I water about once a week. One is in a clay pot, the other is in the glass pot it came in (I don't water that one as often). Because I thought maybe the one in the clay pot had root rot, I repotted into the same pot but added some bark into the mix (it was mostly sphagnum moss previously). From reading online, I thought maybe that there was too much sun as well, so I've since moved the pot away from the window. The leaves, although getting reddish brown, are still firm and don't look like they are dying off. Both the plants have flower stalks. The one with the glass pot is on its way out. The one in the clay pot is a new shoot with buds on the end.

Any thoughts as to the culprit for the darker leaves? My other orchids (all phals) have green leaves, though I notice some are turning colors as well (and not the typical bottom leaf turning color). I've also since put a heavier shade cloth on the top shelf to further reduce the light. Thanks for any help!