Most listings are in the $20's per square foot per year. The Warrenville region is going through a an increase in rates. In the last 3 months, the median rate went up $28 per sqft per year.
Compared to the rest of the Chicagoland market, the Warrenville submarket has higher rates, and you'll need to pay a premium to be in this hot submarket.
In the last 90 days, 9 listings have been made available, which means listings most likley are going fast. You'll want to be prepared to make an offer immediately. About 33% of the listings in the Warrenville are subleases, so you might be able to find a shorter term or below market rent. 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 2,400 sqft. Most buildings in this region are approximately 2 stories. Most buildings in this area were built in 1999 and are Class B.