To get mold alot of air is leaking, a blower door test apx 300 will
identify alot of your issues except furnace which still likely leaks. R
30 is probably under code for your area and definatly not optimal,R 60
may be fo you area-zone. Air can leak in outlets, foam insulation covers
are cheap, up through walls from the basement etc. You may be under
ventilated there are vent size per sq ft recommendations you need to
research, a power vent will just pull out heated air. Your attic door
may not seal, there are alltypes of sizes available, A blower door test
woul eliminate most everything.