On average, listings lease in the $40's per square foot per year. The Westport submarket is going through a decrease in rates. In the last 3 months, the median rate decreased $11 per sqft per year. That's a 20% decline in rent.
Compared to the rest of the Fairfield market, the Westport submarket has higher rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 25 listings have been made available, which means leases most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 4% of the listings in the Westport are subleases, so you will probably need to consider the implications of signing a direct lease with the building. 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 2,500 sqft. Most properties in this region are around 2 stories. Most buildings in this market were built in 1978 and are Class A.