If she needs more air to her room and you can physically install another line then that is the best idea.
Inline boosters are noisy and use a lot of elec $$ and rarely do a good job.
In the Winter just shut off the manual damper which you should have installed in it.
Inline boosters are noisy and use a lot of elec $$ and rarely do a good job.
In the Winter just shut off the manual damper which you should have installed in it.