What part of the country do you live in?
When I built my combined hangar/ home 12 years ago, Nationwide Insurance would not insure me. Whomever I spoke with took the matter to their underwriters and their choice was not to get into the hangar/home type of coverage. The perceived risks, are based on the underwriters ignorance.
If you live in the Pacific Northwest, where Enumclaw Insurance writes coverage, their rates are as good as I have found for our type of dwelling with hangar attached. Enumclaw Insurance is a highly rated company that only insures in the northwest area that has not had any of the catastrophic losses that some of the other bigger companies, ie, Safeco, State Farm have due to hurricanes, etc. and their premiums really reflect that. According to the local Enumclaw agent, he had the company underwriters come to look at this airpark and they were excited about providing coverage for this community.
For the first 8 years or so of ownership of my hangar/home, Country Companies covered me, but at nearly double the cost of Enumclaw. Country Companies did not really understand what they were covering, other than that it was a house with a big garage, even though they were informed what it was, and the agent came to look at the place.
Jake