Are rental homes protected under homeowners insurance policies?

No. In the united States, Homeowners Insurance polices are Null and Void at the moment your home is rented unless you have had the policy endorsed for rental property coverage. This is often referred to as "Landlords Insurance" and requires a different policy form known a "Dwelling Policy". Most Insurers will simply cancel the old Homeowners policy and issue a new "Dwelling Policy" form to cover you as this is the appropriate policy form.

Your landlord's insurance policy, or "Dwelling Policy" will cover your rented home. It is certainly possible to have property and liability insurance on a rented property but not on a traditional homeowners Insurance policy form.