Hi C_Brat,
Welcome to the OB!
I use a light meter to measure the light levels for all my orchids.
Phalaenopsis can flower(?) with low level light 300-500 fc, however 1000- 1500 fc is the preferred level (medium light- see below).
If you don't have a light meter, you can roughly estimate by using the shadows casted by your hand:
* A sharp edge to your shadow = High Light
* A soft edge shadow = medium to low light
* No shadow at all = the light is insufficient for your plant to flower.
I hope that helps!