On average, listings lease in the $10's per square foot per year. The Northwest Side region is going through a decline in rates. In the last 3 months, the median rate fell $9 per sqft per year. That's a 32% decrease in rent.
Compared to the rest of the Chicagoland market, the Northwest Side submarket has less expensive rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 70 listings have been listed, so you'll want to check back regularly for new listings. About 1% of the office spaces in the Northwest Side are subleases, so you will probably have to consider a longer term lease. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 2,340 sqft. Most buildings in this region are around 2 floors. Most buildings in this market were built in 1950 and are Class A.