The typical asking rate per listing is in the $30's per square foot per year. The Napa region is experiencing a a rise in rates. In the last 3 months, the median rate increased $6 per sqft per year. That's a 22% increase in rent.
In the last 90 days, 18 listings have come on the market, which means new listings might be going fast. You'll want to be prepared to make an offer immediately. 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 1,320 sqft. Most properties in this market are approximately 1 stories. Most buildings in this market were built in 1983 and are Class A.