The typical asking rate per listing is in the $10's per square foot per year. The Northbrook submarket is experiencing a decline in rates. In the last 3 months, the median rate decreased $2 per sqft per year. That's a 9% decline in rent.
In the last 90 days, 2 listings have been made available, which means leases 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.
The standard measurement for office space in this area is around 560 sqft. Most buildings in this area are around 4 stories. Most buildings in this region were built in 1977.