If the air conditioning is an installed unit, not a window unit you should leave it.
The hot water heater is installed and part of the house. The blinds you can take if you want to.Don't risk being charged with theft.
Lynn is correct and the banks may be overwhelmed but they still may come after you. I see many foreclosures that have been stripped of so much stuff. I saw an agent talking about a house being"coperr-free"!