Compared to the rest of the Bay Area market, the Napa submarket has less expensive rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 15 listings have been listed, which means new listings most likley are going fast. You'll want to be prepared to tour spaces as quick as possible. 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 1,610 sqft. Most buildings in this region are close to 1 floors. Most buildings in this region were built in 1978 and are Class B.