Sizing an air-source heat pump – GreenBuildingAdvisor

I’m sizing a new heat pump system. Trying to decide between Tempstar (Carrier equivalent) systems rated at 24K BTU/hr ( AHRI Cert#: 215319085) and 30K BTU/hr ( 215319098).

As of right now, I estimate my design load at 5F to be 25000 BTU/hr. There’s less low-load cycling for the 24K system and less unmet load for the 30K. How do you balance those out?

Is there an ideal balance point?

BTW, the specs are identical to similar Carrier systems, so I assume they are just relabeled. Does that seem correct?