Newbie looking for help, yellow leaves

[yenneffer]

Thank you for your help! The orchid was placed on a bright spot but not with direct sunlight. The temperature sure should be over 16C, but the orchid was nearby a window that was opened quite often so maybe that didn't help. I tried moving it to a different room where the window isn't being opened as often. The buds that fell off looked dried, do you think it was because I didn't water it enough or did cold do that?

The roots in the pot look green, some with a silvery layer. but the roots that are out in the air seem dry.

I haven't tried dunking it in water completely yet. If I do that, how long should I keep it in the water? I understand the water probably shouldn't touch the leaves if that can be a problem.