On average, listings lease in the $20's per square foot per year. The North Philadelphia region is going through a a rise in rates. In the last 3 months, the median rate increased $2 per sqft per year. That's a 8% increase in rent.
Compared to the rest of the Philadelphia market, the North Philadelphia region has lower rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 22 listings have come on the market, which means new listings most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 5,820 sqft, there are still 0 office spaces below 2,000 sqft. Most properties in this area are around 4 floors. Most buildings in this market were built in 1938 and are Class B.