Insurance for an apartment complex vs a duplex

[Edith TenBroek]

So we are considering investing in some property with part of my husband's retirement account.  A friend told me that insurance rates on apartments are much higher than on a duplex or sfh.  Can someone explain this further?  I'm trying to understand if it's an actual rate difference (commercial property vs non-commercial property), or if it's a difference in metrics based on rents etc.  Am I as clear as mud?

Thanks!

Edie