On average, listings lease in the $20's per square foot per year. The Northbrook submarket is experiencing a decrease in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 11% decline in rent.
Compared to the rest of the Chicagoland market, the Northbrook submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 32 listings have come on the market, which means spaces are probably going fast. You'll want to be prepared to make an offer immediately. 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 1,870 sqft. Most properties in this market are close to 4 floors. Most buildings in this area were built in 1980 and are Class A.