Your Aralia is not showing any evidence of chilling damage. If your home and windows are reasonably well insulated, then outside cold should not be an issue. There is no substitute for good light.
I know from personal experience caring for dozens of Aralias that they do just fine even in very low humidity as long as the roots are properly hydrated.
I don't recommend poking around in the roots as that can cause serious damage if you don't know what you are doing.
