Where do I put home insurance costs

Deduct on Sch E. Be sure that your home owners policy covers you for rental activity. Many do not in which case it could be argued that your insurance costs bear no relation to your business activity and so are not deductible. In any event, only a por rata share of the cost can be deducted. Know that you don’t have to report rental income if rental was for 14 days or less. 

Assuming you're reporting on SCH E, the rental expenses section has a box specifically for insurance. It gets reported on line 9 of the SCH E.

Note that if you are renting out a room or two in your house, then you have to prorate the insurance accordingly.

or are you asking about it for the home office deduction?