24V DC Window Air Conditioner & Heater runs directly off batteryOnly takes 350 500 watts to run and operates directly off your 24 volt battery. The absolutely cheapest way to run this would be to wire it to two car batteries in series for 24 volt operation. You can also select a package with battery, solar, or charge controller to have a fully functional self contained cooling and heating system for total off grid operations. See unit in VR in your building check out the 3d model picture. 6000 9000 BTU h window