On average, listings lease in the $30's per square foot per year. The Fairfax region is seeing a a boost in rates. In the last 3 months, the median rate increased $1 per sqft per year. That's a 4% increase in rent.
Compared to the rest of the Washington D.C. market, the Fairfax region has less expensive rates, so you should have no trouble finding a great deal in this undervalued region.
In the last 90 days, 31 listings have been posted online, which means new listings are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 194% of the office spaces in the Fairfax 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 posted, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,230 sqft. Most properties in this market are approximately 3 stories. Most buildings in this region were built in 1985 and are Class B.