On average, listings lease in the $30's per square foot per year. The Napa region is seeing a decrease in rates. In the last 3 months, the median rate decreased $1 per sqft per year. That's a 4% decrease in rent.
In the last 90 days, 22 listings have come on the market, which means leases are probably leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,530 sqft. Most properties in this region are around 1 stories. Most buildings in this market were built in 1983 and are Class A.