Squirrels and expensive heat

The location is great. But, the landlady routinely crosses the line of what is appropriate for a landlord (uses your cleaning supplies, leaves huge messes after "fixing" things - seriously, hide your vaccuum cleaner if anyone is coming to fix the furnace or repair drywall.). The furnace is ancient and due to multiple years of squirrel infestations in the attic, all the insulation has been removed. We were spending more on heat in this house than any rental I have ever had before, and it was still freezing in the winter. And, don't put anything in the garage that you care about. If the squirrels don't rip it apart, someone will walk in and take off with it.