Most listings are in the $20's per square foot per year. The New Hampshire submarket is going through a an increase in rates. In the last 3 months, the median rate rose $0 per sqft per year. That's a 1% increase in rent.
In the last 90 days, 1552 listings have been listed, so you'll want to check back regularly for new listings. About 1% of the listings in the New Hampshire are subleases, so you will probably need to sign a longer term lease with the landlord directly. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,740 sqft. Most buildings in this region are approximately 2 stories. Most buildings in this market were built in 1950 and are Class Class B.