Most listings are in the $10's per square foot per year. The Brooklyn Heights submarket is going through a decline in rates. In the last 3 months, the median rate decreased $7 per sqft per year. That's a 31% decrease in rent.
In the last 90 days, 5 listings have been posted online, which means new listings most likley are going fast. You'll want to be prepared to make an offer immediately. About 60% of the office spaces in the Brooklyn Heights 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.
Even though the median size is 22,650 sqft, there are still 0 leases below 2,000 sqft. Most buildings in this market are approximately 2 floors. Most buildings in this region were built in 1999 and are Class C.