The typical asking rate per listing is in the $10's per square foot per year. The Irving Park region is going through a a boost in rates. In the last 3 months, the median rate went up $16 per sqft per year. That's a Inf% increase in rent.
Compared to the rest of the Chicagoland market, the Irving Park region has less expensive rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 1 listings have been listed, which means office spaces might be leasing quickly. You'll want to be prepared to tour spaces as quick as possible. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 800 sqft. Most properties in this market are close to 2 floors. Most buildings in this market were built in 1952 and are Class B.