Mon–Fri, 10:00 a.m. to 5:00 p.m. Pacific
customer.service@paizo.com
Search this Thread:
Do the rimed Ray of frost heightened to Xth level with X>=1 entangle for X rounds? My search fu is ineffective on that.
Yes, Heighten spell counts as a higher level spell for all purposes.
HOWEVER, IIRC, the cost of Heighten Spell is inherently irreducible. So you will be spending >0 spell slots on each casting no matter what.