I'd say 60% max in the basement, to avoid mold.

Nick

So far I can keep the Basement's humdiity level below 60% as long as I leave
the blower motor on the Furnace/AC system turned on all the time. This
causes some of the basement air to circulate throughout the rest of the
house (with the rest of the house still having humidity below 50%).

Would I be better off with a dehumidifier rather than leaving the blower
motor on all summer?

Thanks,

J.