A 1460 sf cape cod style home (1-1/2 story) in south jersey near philadelphia; will 2-1/2 ton condenser be big enough to cool this house?

That is very difficult to say unless you have had a manual J done on the structure because everything else will be a guess and with utility bills so high you do not want to guess on size.

Manual J and other info

EERE Consumer's Guide: Sizing Heating and Cooling Systems (http://www.eere.energy.gov/consumer/your_home/space_heating_cooling/index.cfm/mytopic=12340)

Hvac is correct. But you can find the manual j online if you care to work on it yourself. www.mrhvac.com/manualjshort.htm